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US3711961A Expired / Lapsed US ⏱️ 0.0 years remaining

Heat shrink tunnel

Assignee: Gilbreth Co
•
Filing: 1970-11-25
•
Granted: 1973-01-23
•
Expires: 1990-11-25
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Abstract

Abstract A heat shrink tunnel comprising an enclosure, a conveyor to conduct articles through the enclosure from an upstream point to a downstream point, conduit means to deliver hot air to the enclosure, partition means to divide the conduit means into first and second paths, said first path being relatively long as compared with said second path, a source of hot air, means to force the hot air in a generally upstream direction in the two paths of the conduit means, a first slit in the conduit means at an upstream point, communicating with said enclosure to allow hot air in the first path to enter the enclosure in a narrow band and a second slit in the conduit means spaced downstream of the first slit and also communicating with the enclosure to allow hot air to enter the enclosure in a narrow band at a point that is downstream from the first slit whereby the air entering through the second slit and at the downstream location is relatively hot. In many instances the air entering through the first slit at the upstream location is somewhat cooler than the air entering through the second slit, and in such instances the articles being transported by the conveyor are first subjected to a warm zone and then as the articles move downstream are subjected to a hot zone in order to exert a shrinking effect upon a thermoplastic synthetic resin that is wrapped on the articles. Hot spots adjacent the top of the tunnel are avoided since the warm or hot air is admitted to the tunnel in a narrow band that is normally not directed toward the top of the tunnel.

Inventors

  • 👤 J Spiegel
  • 👤 A Hurewitz

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 16:12
CPC Classifications
B; B29; B29C; B29C63/00; B29C63/38; B29C63/42; B29C63/423; B65; B65B; B65B53/00; B65B53/02; B65B53/06; B65B53/063; B65D; B65D41/00; B65D41/02; B65D41/24; B67; B67B; B67B5/00; B67B5/03; B67B5/036; B29C35/00; B29C35/02; B29C35/04; B29C35/045

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 175 words
A heat shrink tunnel comprising an enclosure, a conveyor to conduct articles through the enclosure from an upstream point to a downstreAm point, conduit means located on each side of said tunnel to deliver hot air to the enclosure, means to force hot air through said conduit means and into said enclosure by way of first and second slits in said conduit means, such that hot air will enter said enclosure in a narrow band, said first and second slits being located on each side of said tunnel in order to provide opposing narrow bands of hot air both at an upstream point and at a downstream point, with such slits being adjustable in both length and orientation, partition means to divide said conduit means into at least first and second paths, said first path being relatively long as compared with said second path whereby air travelling in said first path becomes somewhat cooled and is fed into an upstream slit and relatively hot air in said second path is fed into said downstream slit.
Claim 2
Dependent Claim 175 words
A heat shrink tunnel comprising an enclosure, a conveyor to conduct articles through the enclosure from an upstream point to a downstreAm point, conduit means located on each side of said tunnel to deliver hot air to the enclosure, means to force hot air through said conduit means and into said enclosure by way of first and second slits in said conduit means, such that hot air will enter said enclosure in a narrow band, said first and second slits being located on each side of said tunnel in order to provide opposing narrow bands of hot air both at an upstream point and at a downstream point, with such slits being adjustable in both length and orientation, partition means to divide said conduit means into at least first and second paths, said first path being relatively long as compared with said second path whereby air travelling in said first path becomes somewhat cooled and is fed into an upstream slit and relatively hot air in said second path is fed into said downstream slit.
Claim 3
Dependent Claim 27 words
The heat shrink tunnel of claim 1 including a centering device positioned adjacent the upstream entrance to said enclosure in order to center articles on said conveyor.
Claim 4
Dependent Claim 24 words
The heat shrink tunnel of claim 1 wherein said enclosure is suspended from vertical rods and said conveyor is supported upon a horizontal web.
Claim 5
Dependent Claim 27 words
The heat shrink tunnel of claim 1 wherein said second path is blocked upstream of said second slit but in the general area of said second slit.
Claim 6
Dependent Claim 45 words
The heat shrink tunnel of claim 1 including means for leading streams of hot air into each end of the conduit means, flowing in opposite directions, each hot air stream flowing through upstream and downstream slits provided in the conduit means and into the enclosure.
Claim 7
Dependent Claim 29 words
The heat shrink tunnel of claim 5 wherein the opposing paths of hot air are effectively blocked between the slits and across the full area of the conduit means.

References Cited (Backward Citations)

US2483719A Cited
US3526752A Cited
US3430358A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-01-23 1976-07-24 1977-01-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-01-23 1980-07-24 1981-01-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-01-23 1984-07-24 1985-01-23 $7700.00 Window Closed / Lapsed

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