US3760154A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for heat-shrinking a plastic film on a load
Assignee: Signode Corp
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Filing: 1972-02-29
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Granted: 1973-09-18
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Expires: 1992-02-29
Abstract
Abstract A method and apparatus for applying a protective covering to a load by pulling the open end of a heat-shrinkable inverted film bag downwardly over the load until the lower rim of the bag appreciably overhangs the lower end of the load, initially directing infrared radiant heat on the overhanging rim region of the bag to rapidly shrink the same beneath the load, subsequently directing additional infrared heat inwardly through the sides and closed top of the bag and against the load to establish surface heating of the load and consequent outward reflection of infrared heat through the sides and top of the bag to enhance and rapidify shrinking thereof with a consequent pulling of the underlying pre-shrunk rim region of the bag upwardly to thus establish a seal between such rim region and the bottom of the load and inhibit escape of heated air from the bag, such shrinking of the sides of the bag serving to place the thus covered load under both horizontal and vertical compression.
Inventors
- 👤 A Konger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:51
CPC Classifications
B; B65; B65B; B65B53/00; B65B53/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
392 words
Apparatus for heat shrinking an inverted bag of shrinkable plastic film which is positioned about a generally rectilinear load with its open lower rim region depending in apron-like fashion below the level of the bottom of the load, said apparatus comprising an elongated conveyor for conducting the bagged load continuously and unidirectionally, an arch-like heating oven straddling said conveyor and establishing an open-ended heating tunnel provided with entrance and exit openings and having a horizontal top wall above the conveyor and vertical side walls on opposite sides of the conveyor, means within the tunnel establishing a preheating zone adjacent the entrance end thereof, an intermediate heating zone, and a postheating zone adjacent the exit end of the tunnel, means for actuating the conveyor to move the bagged load forwardly through said zones successively and in the order named, a pair of infrared heating units longitudinally coextensive with and disposed in said preheating zone on opposite sides of the conveyor and below the effective level thereof and arranged to direct radiant heat upwardly and inwardly of the tunnel for heating said depending apron-like rim region of the bag film to shrink the latter beneath said bottom side of the load as the bagged load enters the tunnel, a second pair of infrared heating units longitudinally coextensive with and disposed in the intermediate zone on opposite sides of the conveyor and disposed below the effective level thereof and similarly arranged to direct radiant heat upwardly and inwardly of the tunnel against the inwardly shrunk rim region of the bag film as the bagged load progresses through the tunnel, a series of infrared heating units longitudinally coextensive with and disposed in said intermediate zone on opposite sides of the conveyor, extending from a region adjacent the effective level thereof immediately above said second pair of heating units to a region adjacent the top of the tunnel, and arranged to direct radiant heat laterally and horizontally inwardly against the sides of the bagged load during progression of the same through the tunnel, and a third pair of infrared heating units longitudinally coextensive with and disposed in said postheating zone on opposite sides of the conveyor and below the effective level thereof and arranged to direct radiant heat upwardly and inwardly of the tunnel against said inwardly shrunk rim as the bagged load emerges from the tunnel.
Claim 2
Dependent Claim
392 words
Apparatus for heat shrinking an inverted bag of shrinkable plastic film which is positioned about a generally rectilinear load with its open lower rim region depending in apron-like fashion below the level of the bottom of the load, said apparatus comprising an elongated conveyor for conducting the bagged load continuously and unidirectionally, an arch-like heating oven straddling said conveyor and establishing an open-ended heating tunnel provided with entrance and exit openings and having a horizontal top wall above the conveyor and vertical side walls on opposite sides of the conveyor, means within the tunnel establishing a preheating zone adjacent the entrance end thereof, an intermediate heating zone, and a postheating zone adjacent the exit end of the tunnel, means for actuating the conveyor to move the bagged load forwardly through said zones successively and in the order named, a pair of infrared heating units longitudinally coextensive with and disposed in said preheating zone on opposite sides of the conveyor and below the effective level thereof and arranged to direct radiant heat upwardly and inwardly of the tunnel for heating said depending apron-like rim region of the bag film to shrink the latter beneath said bottom side of the load as the bagged load enters the tunnel, a second pair of infrared heating units longitudinally coextensive with and disposed in the intermediate zone on opposite sides of the conveyor and disposed below the effective level thereof and similarly arranged to direct radiant heat upwardly and inwardly of the tunnel against the inwardly shrunk rim region of the bag film as the bagged load progresses through the tunnel, a series of infrared heating units longitudinally coextensive with and disposed in said intermediate zone on opposite sides of the conveyor, extending from a region adjacent the effective level thereof immediately above said second pair of heating units to a region adjacent the top of the tunnel, and arranged to direct radiant heat laterally and horizontally inwardly against the sides of the bagged load during progression of the same through the tunnel, and a third pair of infrared heating units longitudinally coextensive with and disposed in said postheating zone on opposite sides of the conveyor and below the effective level thereof and arranged to direct radiant heat upwardly and inwardly of the tunnel against said inwardly shrunk rim as the bagged load emerges from the tunnel.
Claim 3
Dependent Claim
51 words
Apparatus as set forth in claim 1 including, additionally, a third series of infrared heating units longitudinally coextensive with said intermediate heating zone, disposed directly above the conveyor and arranged to direct radiant heat vertically downwardly against the top of the bagged load during progression of the same through the tunnel.
Claim 4
Dependent Claim
54 words
Apparatus as set forth in claim 2 including, additionally, a fourth series of infrared heating units disposed within the confines of the conveyor and substantially coextensive with said intermediate zone and arranged to direct radiant heat vertically upwardly against the bottom wall of the load and the underlying shrunk rim region of the bag.
Claim 5
Dependent Claim
47 words
Apparatus as set forth in claim 2, wherein said oven embodies a fixed framework including four quadrilaterally arranged vertical corner posts, a sheet metal oven casing infinitely and vertically adjustable on and supported by said corner posts and establishing said top and side walls of the tunnel.
Claim 6
Dependent Claim
275 words
Apparatus as set forth in claim 2, wherein said oven embodies a fixed framework including a pair of vertically disposed front corner pOsts and a pair of vertically disposed rear corner posts, a relatively large inverted front arch frame supported by and vertically adjustable on said front corner posts, a similar inverted rear arch frame supported by and vertically adjustable on said rear corner posts, and an oven casing supported by said arch frame and vertically adjustable bodily therewith, said casing including a relatively small first arch frame rearwardly of said rear arch frame and establishing an entrance opening for the tunnel, a relatively small second arch frame rearwardly of said rear arch frame and establishing an entrance opening for the tunnel, diverging sheet metal reflector sheets extending between the side legs of the second and rear arch frames, a sloping top reflector sheet extending between the arch portions of the second and rear arch frames, gusset-like reflector sheets extending between the adjacent edges of the latter diverging and sloping reflector sheets, said reflector sheets establishing a generally frusto-pyramidal entrance vestibule for the tunnel, a relatively small third arch frame forwardly of said front arch frame and establishing an exit opening for the tunnel, diverging sheet metal reflector sheets extending between the side legs of the third and front arch frames, a sloping top reflector sheet extending between the arch portions of the third and front arch frames, gusset-like reflector sheets extending between the adjacent edges of the latter diverging and sloping reflector sheets, the reflector sheets which extend between the third and front arch frames establishing a generally frusto-pyramidal exit vestibule for the tunnel.
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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) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |