Patent US4781188A successfully refreshed from Google Patents.
US3864446A
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Method of converting corrugated pipe molding machine
Assignee: Plastic Tubing Inc
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Filing: 1973-12-10
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Granted: 1975-02-04
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Expires: 1993-12-10
Abstract
Abstract A blow-molding machine for molding corrugated plastic pipe having uninterrupted annular ribs thereon is converted for forming corrugated plastic pipe having interrupting gaps or recesses in certain annular ribs of corrugated pipe being formed. Essentially the conversion is effected by positioning and securing relatively short inserts or segmental blocks in otherwise uninterrupted semicircular valleys of cooperating pairs of semitubular mold sections of dies between and against which the plastic pipe is molded.
Inventors
- 👤 Ernest J Maroschak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:31
CPC Classifications
B; B29; B29D; B29D23/00; B29D23/18; B29C; B29C33/00; B29C33/30; B29C33/306; B29C48/00; B29C48/03; B29C48/09; B29C48/13; B29C48/25; B29C48/256; B29C48/2566; B29C48/30; B29C48/303; B29C49/00; B29C49/0015; B29C49/0021; F; F16; F16L; F16L11/00; F16L11/04; F16L11/11; F16L11/111; F16L11/14; F16L11/15; B29C49/42; B29C49/48; B29C2049/4879; B29C2049/4881; B29C2793/00; B29C2793/0045; B29C33/42; B29L; B29L2023/00; B29L2023/18; Y; Y10; Y10S; Y10S264/00; Y10S264/52
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
146 words
In a method of molding plastic pipe wherein an annular tube of molten plastic material is extruded and directed into a molding machine having pairs of cooperating mold sections arranged to receive the extruded tube and move the same through an elongate molding zone and wherein at least some of the mold sections have alternating semicircular transverse ribs and valleys with the ribs and valleys of one section of each pair cooperating with the ribs and valleys of the other section of the same pair to form respective annular valleys and ribs on the plastic pipe being molded therein, the improvement comprising positioning and securing at least one insert in one of the valleys of at least one of the mold sections and thereafter molding plastic pipe against the mold section whereby the insert serves for forming an interrupting gap in the corresponding rib being molded.
Claim 2
Dependent Claim
146 words
In a method of molding plastic pipe wherein an annular tube of molten plastic material is extruded and directed into a molding machine having pairs of cooperating mold sections arranged to receive the extruded tube and move the same through an elongate molding zone and wherein at least some of the mold sections have alternating semicircular transverse ribs and valleys with the ribs and valleys of one section of each pair cooperating with the ribs and valleys of the other section of the same pair to form respective annular valleys and ribs on the plastic pipe being molded therein, the improvement comprising positioning and securing at least one insert in one of the valleys of at least one of the mold sections and thereafter molding plastic pipe against the mold section whereby the insert serves for forming an interrupting gap in the corresponding rib being molded.
Claim 3
Dependent Claim
64 words
A method according to claim 1, which includes positioning and securing at least one additional insert in said one of the valleys in spaced relation from said first named insert with the combined length of both inserts being substantially less than that of the respective valley, whereby at least two interrupting gaps are formed in the same rib during molding of the plastic pipe.
Claim 4
Dependent Claim
33 words
A method according to claim 1, which includes forming the insert of a thickness substantially less than the depth of the respective valley before positioning and securing the insert in the respective valley.
Claim 5
Dependent Claim
33 words
A method according to claim 1, which includes forming the insert of a thickness substantially equal to the depth of the respective valley before positioning and securing the insert in the respective valley.
Claim 6
Dependent Claim
25 words
A method according to claim 1, which includes forming substantially perpendicular ends on the insert before positioning and securing the same in the respective valley.
Claim 7
Dependent Claim
25 words
A method according to claim 1, which includes forming beveled opposite ends on the insert before positioning and securing the same in the respective valley.
Claim 8
Dependent Claim
37 words
A method according to claim 1, which includes positioning and securing an additional insert in the cooperating valley of the other mold section of the same pair so that both inserts are in the same annular valley.
Claim 9
Dependent Claim
32 words
A method according to claim 1, which includes positioning and securing at least one insert in one of the valleys of one mold section of each of a majority of the pairs.
Claim 10
Dependent Claim
31 words
A method according to claim 1, which includes positioning and securing three spaced apart inserts in one of the valleys of one mold section of each a majority of the pairs.
Claim 11
Dependent Claim
28 words
A method according to claim 1, which includes positioning and securing three spaced apart inserts in one of the annular valleys of each cooperating pair of mold sections.
Claim 12
Dependent Claim
39 words
A method of according to claim 1, wherein the step of securing the insert in the valley of the mold section comprises releasably securing the same to readily permit later reconverting the mold section back to its original form.
Claim 13
Dependent Claim
189 words
In a method of molding plastic pipe wherein an annular tube of molten plastic material is extruded and directed into a molding machine having pairs of cooperating mold sections arranged to receive the extruded tube and move the same through an elongate molding zone and wherein at least some of the mold sections have alternating semicircular transverse ribs and valleys will the ribs and valleys of one section of each pair cooperating with the ribs and vallesy of the other section of the same pair to form respective annular valleys and ribs on the plastic pipe being molded therein, the improvement comprising forming a plurality of inserts, each of a width corresponding to that of the valleys of the mold section and of an arcuate length substantially less than that of the valleys and of a thickness not exceeding the depth of the valleys, positioning and securing the inserts in spaced apart relation in one of the valleys of at least one of the mold sections and thereafter molding plastic pipe against the mold section whereby the inserts serve for forming interrupting gaps in the corresponding rib being molded.
Claim 14
Dependent Claim
189 words
In a method of molding plastic pipe wherein an annular tube of molten plastic material is extruded and directed into a molding machine having pairs of cooperating mold sections arranged to receive the extruded tube and move the same through an elongate molding zone and wherein at least some of the mold sections have alternating semicircular transverse ribs and valleys will the ribs and valleys of one section of each pair cooperating with the ribs and vallesy of the other section of the same pair to form respective annular valleys and ribs on the plastic pipe being molded therein, the improvement comprising forming a plurality of inserts, each of a width corresponding to that of the valleys of the mold section and of an arcuate length substantially less than that of the valleys and of a thickness not exceeding the depth of the valleys, positioning and securing the inserts in spaced apart relation in one of the valleys of at least one of the mold sections and thereafter molding plastic pipe against the mold section whereby the inserts serve for forming interrupting gaps in the corresponding rib being molded.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |