Patent US3185194A successfully refreshed from Google Patents.
Patent US3910747A successfully refreshed from Google Patents.
US3910747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus having improved sheet clamping means for forming plastic sheets
Assignee: Formex Manufacturing Inc
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Filing: 1974-09-23
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Granted: 1975-10-07
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Expires: 1994-09-23
Abstract
Abstract Improvements in thermoplastic sheet edge clamping means useful in a vacuum forming machine are disclosed. The clamping means are carried on spaced apart, open frameworks used for transferring thermoplastic sheets between heating and molding stations, for positioning the sheets at these stations and for removing molded product from the molding station of the vacuum molding machine. The sheet edge clamping means have piston and cylinder actuators with conduit means extending from an actuator valve and pressure fluid supply and with a piston bypass conduit on at least one of the actuators whereby a continuous bleed of pressure fluid can be circulated through the actuators. This continuous circulation of fluid cools the actuators when the frameworks are in the heating station and thereby avoids unintentional release of the sheets by failure of the actuators.
Inventors
- 👤 Donald E Dean
- 👤 Jr John Alesi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:58
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/18; B29C51/26; B29C51/261; B29C51/262; B29C51/14; B29L; B29L2009/00; B29L2009/001; Y; Y10; Y10S; Y10S425/00; Y10S425/048
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
210 words
In a vacuum-forming machine having transfer means including at least one open frameworks formed of frame bar members for transferring sheets of thermoplastic to a heating station and positioning said sheets therein between heating elements where said sheets are heated to a forming temperatures and to a molding station and positioning said sheets therein between opposed die faces where said sheets are molded into a formed product, the improved sheet clamping means carried on said transfer means which comprises a clamping assembly carried on at least one of said frame bar members for engaging an edge of said thermoplastic sheet, including opposed jaws carried by said assembly to grip opposite sides of said sheet with at least one of said jaws being pivotally mounted on said clamping assembly and including a reciprocable piston and cylinder actuator therefore having fluid pressure ports at opposite ends of said cylinder, a source of pressure fluid, selector valve means and conduits between said source of pressure fluid, valve means and ports whereby pressure fluid can be applied to a selected one side of said piston and exhausted from the opposite side thereof and pressure fluid bleed means carried by said actuator whereby a continuous flow of pressure fluid can be maintained through said actuator.
Claim 2
Dependent Claim
210 words
In a vacuum-forming machine having transfer means including at least one open frameworks formed of frame bar members for transferring sheets of thermoplastic to a heating station and positioning said sheets therein between heating elements where said sheets are heated to a forming temperatures and to a molding station and positioning said sheets therein between opposed die faces where said sheets are molded into a formed product, the improved sheet clamping means carried on said transfer means which comprises a clamping assembly carried on at least one of said frame bar members for engaging an edge of said thermoplastic sheet, including opposed jaws carried by said assembly to grip opposite sides of said sheet with at least one of said jaws being pivotally mounted on said clamping assembly and including a reciprocable piston and cylinder actuator therefore having fluid pressure ports at opposite ends of said cylinder, a source of pressure fluid, selector valve means and conduits between said source of pressure fluid, valve means and ports whereby pressure fluid can be applied to a selected one side of said piston and exhausted from the opposite side thereof and pressure fluid bleed means carried by said actuator whereby a continuous flow of pressure fluid can be maintained through said actuator.
Claim 3
Dependent Claim
16 words
The machine of claim 1 wherein said clamping means comprises a plurality of said clamping assemblies.
Claim 4
Dependent Claim
62 words
The machine of claim 2 wherein said clamp assemblies are modular units, each comprising a base bracket bearing opposed flange means surrounding the supporting bar member of said open frameworks and bearing locking means for fixedly securing said assembly to said bar member, a shelf extension therefrom defining the lower of said jaws and the upper of said jaws pivotally carried thereon.
Claim 5
Dependent Claim
65 words
The machine of claim 2 wherein a plurality of conduits are provided to interconnect the ports at the rear of a plurality of said actuators and a second plurality of conduits are provided to interconnect the ports at the front of a plurality of said actuators with the cylinder of one of said actuators bearing said fluid bleed means interconnecting its rear and front ports.
Claim 6
Dependent Claim
36 words
The machine of claim 1 wherein said pressure fluid bleed means comprises a second pair of ports, one each at opposite ends of said cylinder with conduit means interconnecting said ports and bearing flow control means.
Claim 7
Dependent Claim
27 words
The machine of claim 1 wherein the uppermost jaw bears a link member pivotally attached thereto and, at its opposite end, pivotally attached to said base bracket.
Claim 8
Dependent Claim
34 words
The machine of claim 1 wherein one end of the piston and cylinder actuator is connected to said uppermost jaw and its opposite end is connected to an arm dependent from said base bracket.
Claim 9
Dependent Claim
16 words
The machine of claim 1 wherein the upper jaw carries a plurality of downwardly dependent prongs.
Claim 10
Dependent Claim
32 words
The machine of claim 1 wherein said prongs bear threaded shanks engaged in tapped bores in said jaw whereby the force of their engagement with said thermoplastic sheet can be fixedly adjusted.
Claim 11
Dependent Claim
49 words
The machine of claim 1 wherein said transfer means comprises a carousel bearing a plurality of pairs of vertically spaced apart open frameworks rotatably mounted to move said pairs of frameworks between loading-unloading, heating and molding stations and wherein said selector valve means is located at said loading-unloading station.
Claim 12
Dependent Claim
38 words
The machine of claim 10 wherein said selector valve includes an electrically actuated pneumatic solenoid operative to move said selector valve to a position directing said pressure fluid to a selected side of the pistons of said actuators.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |