US3843758A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making and slitting plastic corrugated tubes
Assignee: Plastic Tubing Inc
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Filing: 1972-07-13
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Granted: 1974-10-22
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Expires: 1992-07-13
Abstract
Abstract A method for making plastic corrugated tubes particularly useful for irrigation pipes, and wherein a tube of hot plastic material is extruded into a blow molding zone which molds annular corrugations of alternating ribs and valleys on the tube during forward movement thereof through the molding zone. The thus molded corrugated tube is delivered from the molding zone and fed through a slitting station wherein series of circularly spaced slits are cut in certain valleys of the tube by circularly arranged slitting saws or cutting blades. The slit tube is directed from the slitting station through a cutting station where it is cut into predetermined lengths ready for delivery to a customer.
Inventors
- 👤 E Maroschak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:17
CPC Classifications
B; B26; B26D; B26D3/00; B26D3/16; B26F; B26F1/00; B26F1/0015; B26F1/0023; Y; Y10; Y10S; Y10S264/00; Y10S264/52; Y10S285/00; Y10S285/903
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
220 words
A method of making a plastic corrugated tube and forming slits therein which tube to the steps of extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predetermined speed, feeding the corrugated tube delivered from the molding zone through a slitting station by meshingly engaging the corrugations of the tube with a plurality of forwardly moving teeth with successive teeth entering successive valleys and pushing forwardly against the respective ribs of the corrugated tube, sensing variations in tension in the corrugated tube between the blow molding zone and said feeding and in response thereto varying the rate of movement of the forwardly moving teeth to vary the rate of feed of the tube of substantially accord with the rate of delivery of the tube from the molding zone, cutting slits through certain valleys of the tube being fed as it passes through the slitting station, directing the slit tube from the slitting station through a cutting station, and cutting the tube into predetermined lengths as it passes through the cutting station.
Claim 2
Independent Claim
220 words
A method of making a plastic corrugated tube and forming slits therein which tube to the steps of extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predetermined speed, feeding the corrugated tube delivered from the molding zone through a slitting station by meshingly engaging the corrugations of the tube with a plurality of forwardly moving teeth with successive teeth entering successive valleys and pushing forwardly against the respective ribs of the corrugated tube, sensing variations in tension in the corrugated tube between the blow molding zone and said feeding and in response thereto varying the rate of movement of the forwardly moving teeth to vary the rate of feed of the tube of substantially accord with the rate of delivery of the tube from the molding zone, cutting slits through certain valleys of the tube being fed as it passes through the slitting station, directing the slit tube from the slitting station through a cutting station, and cutting the tube into predetermined lengths as it passes through the cutting station.
Claim 3
Dependent Claim
43 words
A method according to claim 1, wherein the cutting of the tube into predetermined lengths includes successively cutting the corrugated tube into a plurality of uniform lengths, and further including stacking the uniform lengths in nesting relation and tieing them in a bundle.
Claim 4
Dependent Claim
64 words
A method according to claim 1, wherein the step of cutting the tube into predetermined lengths includes directing the leading end of the tube against an element spaced a predetermined distance forwardly of the cutting station, and actuating the cutting station to cut the tube into a corresponding predetermined length in response to engagement of the leading end of the tube with the element.
Claim 5
Dependent Claim
72 words
A method according to claim 1, wherein the step of cutting the tube into predetermined lengths inCludes sensing the linear amount of the corrugated tube being moved forwardly from the molding zone past a particular location in the path of travel of the corrugated tube, and actuating the cutting station to cut the tube in response to each sensing of a predetermined linear amount of the tube being moved past said location.
Claim 6
Dependent Claim
51 words
A method according to claim 1, including winding onto a rotating reel a predetermined length of the corrugated tube being fed, then effecting said cutting of the tube at the cutting station, and then winding the cut terminal portion of the tube onto the reel to form a wound package thereof.
Claim 7
Dependent Claim
42 words
A method according to claim 1, wherein the cutting of slits through certain valleys of the tube as it passes through the slitting station includes cutting a circular series of radial slits around the tube through each of said certain valleys thereof.
Claim 8
Dependent Claim
67 words
A method according to claim 6, wherein the tube being molded is at least about 4 inches in diameter and wherein the cutting of the circular series of radial slits further includes cutting elongate slits in substantially uniformly spaced relation through each of said certain valleys of the tube with each slit extending arcuately of and being of less width than the width of the respective valley.
Claim 9
Dependent Claim
36 words
A method according to claim 6, wherein the cutting of the circular series of radial slits further includes cutting five elongate, substantially uniformly spaced arcuately extending slits through each of said certain valleys of the tube.
Claim 10
Dependent Claim
45 words
A method according to claim 6, wherein the cutting of any given circular series of radial slits around the tube in certain valleys thereof comprises simultaneously moving a set of circularly arranged rotating cutting blades into cutting engagement with the respective valley of the tube.
Claim 11
Dependent Claim
58 words
A method according to claim 1, wherein the cutting of slits through certain valleys of the tube as it passes through the cutting station includes cutting a circular series of radial slits around the tube through each of said certain valleys, and wherein the cutting of the circular series of slits in any given valley is effected simultaneously.
Claim 12
Dependent Claim
44 words
A method according to claim 1, wherein the cutting of slits through certain valleys of the tube as it passes through the slitting station includes simultaneously cutting a circular series of radial slits around the tube through each of two alternately spaced valleys thereof.
Claim 13
Dependent Claim
56 words
A method according to claim 1, wherein the feeding of the corrugated tube through the slitting station includes feeding the tube forwardly in a stepwise manner, and wherein the cutting of slits through certain valleys comprises moving a plurality of rotary cutting blades into cutting engagement with the tube between successive stepwise movements of the tube.
Claim 14
Dependent Claim
77 words
A method according to claim 12, in which the step of feeding the corrugated tube further comprises moving the tube forwardly during the stepwise movements thereof at a rate compensatingly greater than the rate at which the corrugated tube is being delivered from the molding zone and so that the overall rate of movement of the tube through the slitting station is substantially in accord with the rate of delivery of the tube from the molding zone.
Claim 15
Independent Claim
169 words
A method of making a plastic corrugated tube having radial slits therein which comprises the steps of continuously extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predetermined speed, feeding the corrugated tube being delivered from the molding zone successively through slitting and cutting stations, cutting radial slits through certain valleys of the tube being fed as it passes through the slitting station, and cutting the tube into predetermined lengths As it passes through the cutting station, while sensing variations in tension in the corrugated tube between the blow molding zone and said feeding and in response thereto varying the rate of feed of the tube to substantially accord with the rate of delivery of the tube from the molding zone.
Claim 16
Independent Claim
169 words
A method of making a plastic corrugated tube having radial slits therein which comprises the steps of continuously extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predetermined speed, feeding the corrugated tube being delivered from the molding zone successively through slitting and cutting stations, cutting radial slits through certain valleys of the tube being fed as it passes through the slitting station, and cutting the tube into predetermined lengths As it passes through the cutting station, while sensing variations in tension in the corrugated tube between the blow molding zone and said feeding and in response thereto varying the rate of feed of the tube to substantially accord with the rate of delivery of the tube from the molding zone.
Claim 17
Independent Claim
397 words
A method of making a plastic corrugated tube and forming radial slits therein which comprises the steps of extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predeterm ned speed, feeding the corrugated tube delivered from the molding zone through a slitting station by meshingly engaging the corrugations of the tube with the peripheral teeth of at least one forwardly rotating feed gear with successive teeth thereof entering successive valleys and pushing forwardly against the respective ribs of the corrugated tube and while continuously rotating the feed gear at a peripheral speed substantially the same as the rate of delivery of the tube from the molding zone, sensing variations in tension in the corrugated tube in its course from the molding zone to the slitting station and in response thereto varying the peripheral speed of the feed gear to compensatively vary the rate of feed of the tube by the feed gear to substantially accord with the rate of delivery of the tube from the molding zone, causing the tube to dwell in the slitting station at predetermined intervals of predetermined duration by periodically imparting a rearward translational movement to the feed gear at a rate so correlated to the rate of forward rotation of the feed gear that the tube remains at a standstill in the slitting station throughout the rearward translational movement of the feed gear, then imparting a forward translational movement to the feed gear so that the feed gear moves the tube forwardly at a rate equal to the rate of rotation of the feed gear combined with the rate of forward translational movement of the feed gear and such that the overall rate of movement of the tube through the slitting station is substantially the same as the rate of delivery of the tube from the molding zone, cutting radial slits through certain valleys of the tube during each dwell of the tube in the slitting station, directing the slit tube from the slitting station through a cutting station, and cutting the tube into predetermined lengths as it passes through the cutting station.
Claim 18
Independent Claim
397 words
A method of making a plastic corrugated tube and forming radial slits therein which comprises the steps of extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys on the tube during forward movement of the tube through the molding zone and while delivering the corrugated tube from the molding zone at a predeterm ned speed, feeding the corrugated tube delivered from the molding zone through a slitting station by meshingly engaging the corrugations of the tube with the peripheral teeth of at least one forwardly rotating feed gear with successive teeth thereof entering successive valleys and pushing forwardly against the respective ribs of the corrugated tube and while continuously rotating the feed gear at a peripheral speed substantially the same as the rate of delivery of the tube from the molding zone, sensing variations in tension in the corrugated tube in its course from the molding zone to the slitting station and in response thereto varying the peripheral speed of the feed gear to compensatively vary the rate of feed of the tube by the feed gear to substantially accord with the rate of delivery of the tube from the molding zone, causing the tube to dwell in the slitting station at predetermined intervals of predetermined duration by periodically imparting a rearward translational movement to the feed gear at a rate so correlated to the rate of forward rotation of the feed gear that the tube remains at a standstill in the slitting station throughout the rearward translational movement of the feed gear, then imparting a forward translational movement to the feed gear so that the feed gear moves the tube forwardly at a rate equal to the rate of rotation of the feed gear combined with the rate of forward translational movement of the feed gear and such that the overall rate of movement of the tube through the slitting station is substantially the same as the rate of delivery of the tube from the molding zone, cutting radial slits through certain valleys of the tube during each dwell of the tube in the slitting station, directing the slit tube from the slitting station through a cutting station, and cutting the tube into predetermined lengths as it passes through the cutting station.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |