US3590440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clamp mechanism for a plastics injection-molding machine
Assignee: New Britain Machine Co
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Filing: 1969-05-22
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Granted: 1971-07-06
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Expires: 1989-05-22
Abstract
Abstract The invention contemplates vertical-action hydraulic moldpositioning and clamp mechanism carried above the region of moldfilling, in a plastics injection-molding machine having provision for selective horizontal discharge of plasticized melt. The nature of the mold-clamp mechanism is such that it will selfadapt to bending deflections of frame parts, in the presence of high clamp-force pressures. In the hydraulic mechanism disclosed, major displacements are achieved by a relatively low-pressure system, whereas clamp forces are generated by a relatively highpressure system. For safety, the high-pressure operation involves a minimum of displaced fluid, and means are provided to automatically vent the high-pressure system in the event of such downward positioning of parts as is indicative of failure to install a complete mold.
Inventors
- 👤 Francis W Cook Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:24
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/64; B29C45/67; Y; Y10; Y10S; Y10S425/00; Y10S425/223
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
238 words
A plastics injection-molding machine, comprising a base frame, means carried by said frame and including an injection means for selectively discharging plasticized melt on a generally horizontal axis, spaced upper and lower mold-support platens for positioning the sprue hole of vertically separable mold to receive melt discharge from said injection means, said lower platen being directly supported on said frame and said upper platen being vertically movably supported on said frame; the upper platen support comprising pedestal frame means united with said base frame and extending upwardly therefrom in adjacency with the region of lower-platen support, hydraulic means including piston and cylinder elements one of which is secured to said pedestal frame means and the other of which carries said upper platen, said hydraulic elements being actuable vertically for upper platen positioning into and out of mold-clamping relation with said lower platen, radially yieldable seal means between said elements, said hydraulic elements having a closeclearance radially locating relation at essentially a single longitudinally limited region of axial overlap and having otherwise such substantial radial clearance as to permit misalignment of the respective axes of said hydraulic elements against the yielding action of said seal means; whereby in the presence of elastic bending of said pedestal frame means, as during application of mold-clamping pressures to said hydraulic elements, said elements will self-adapt their axial misalignment to achieve uniform mold-clamping action while filling a clamped mold from said injection means.
Claim 2
Dependent Claim
238 words
A plastics injection-molding machine, comprising a base frame, means carried by said frame and including an injection means for selectively discharging plasticized melt on a generally horizontal axis, spaced upper and lower mold-support platens for positioning the sprue hole of vertically separable mold to receive melt discharge from said injection means, said lower platen being directly supported on said frame and said upper platen being vertically movably supported on said frame; the upper platen support comprising pedestal frame means united with said base frame and extending upwardly therefrom in adjacency with the region of lower-platen support, hydraulic means including piston and cylinder elements one of which is secured to said pedestal frame means and the other of which carries said upper platen, said hydraulic elements being actuable vertically for upper platen positioning into and out of mold-clamping relation with said lower platen, radially yieldable seal means between said elements, said hydraulic elements having a closeclearance radially locating relation at essentially a single longitudinally limited region of axial overlap and having otherwise such substantial radial clearance as to permit misalignment of the respective axes of said hydraulic elements against the yielding action of said seal means; whereby in the presence of elastic bending of said pedestal frame means, as during application of mold-clamping pressures to said hydraulic elements, said elements will self-adapt their axial misalignment to achieve uniform mold-clamping action while filling a clamped mold from said injection means.
Claim 3
Dependent Claim
193 words
The machine of claim 1, wherein said hydraulic elements comprise a main cylinder secured to said pedestal frame means and including a head closing the upper end of said cylinder, a main cylindrical ram vertically movable within said cylinder and carrying said upper platen at the lower end of said main ram, said main ram having a cylindrical cavity coaxial with the ram axis and open at the tail end of said ram, a booster ram having sealed slidable relation in said cylindrical cavity and including a fixed elongated tail connection to said head, closure means establishing a sealed slidable relation between said tail connection and the upper end of said main ram, first pressure-fluid communicating means selectively supplying pressure fluid within said cavity to the respective regions above and below said booster ram for vertically actuating said main ram in said main cylinder in a reciprocating cycle of mold-closing and mold-opening displacement of said upper platen, and second pressure-fluid communicating means selectively supplying fluid pressure to the region between said head and the upper end of said main ram for applying mold-clamping pressure when said main ram is in the mold-closed position.
Claim 4
Dependent Claim
130 words
The machine of claim 2, in which the elongation of said hydraulic elements is such that said main ram may be downwardly displaced to a position below normal mold-clamping position, and safety venting means including a passage in said tail connection, said passage including a port near the lower end of said tail connection and vertically positioned to be fully traversed by said closure means only when said main ram has been downwardly displaced beyond its normal mold-clamping position; whereby in the event of downward movement of said main ram Beyond normal mold-clamping position, as may occur when one or more mold parts have not been installed on said platens, any inadvertent supply of mold-clamping pressures will be vented and thus ineffective to apply mold-clamping force to said main ram.
Claim 5
Dependent Claim
113 words
The machine of claim 2, in which said hydraulic means includes a surge tank carried by said pedestal frame means and having fluid connection to said main cylinder, said last-mentioned connection including a prefill valve and means for selectively opening and closing the same; whereby during a downward actuation of said booster ram while said prefill valve is open, hydraulic fluid from said surge tank may be drawn into the region between said head and said main ram; and further whereby after prefill-valve closure when said main ram is in mold-closing position, there may be a minimum of flow of hydraulic pressure fluid in the mold-clamping operation of said second pressure-fluid communicating means.
Claim 6
Dependent Claim
98 words
The machine of claim 2, in which a ram bushing carried by said main cylinder near the lower end thereof provides the guided support of said main ram and is the primary central positioning means for said main ram, said bushing being longitudinally short compared to the total longitudinally telescoped relation of said main ram and cylinder, and there being otherwise said substantial radial clearance relation between said hydraulic elements, whereby said bushing establishes a downwardly located region of accommodation of the mold-clamping axis to such main-cylinder axis misalignments as result from bending deflection of said pedestal-frame means.
Claim 7
Dependent Claim
64 words
The machine according to claim 2, in which said main ram includes means closing the cylindrical cavity thereof beneath said booster ram and in which second pressure-fluid communicating means selectively supplies fluid pressure to the region between said booster ram and the main-ram closure therebelow, whereby enhanced clamping effort is realized from the combined forces over said main ram and over said booster ram.
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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) | 1974-07-05 | 1975-01-04 | 1975-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-05 | 1979-01-04 | 1979-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-05 | 1983-01-04 | 1983-07-06 | $7700.00 | Window Closed / Lapsed |