US3581458A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of shrinking a sleeve- or cap-shaped wrapping of heat-shrinkable plastic sheet surrounding a transport unit and an apparatus for carrying out the method
Abstract Shrinking of a contractive wrapping of heat-shrinkable plastic sheet surrounding a transport unit composed of collected or piled objects, preferably on a pallet, is accomplished by directional heat radiation from electrical emitters mounted on one or more carriers and by effecting a relative movement between the wrapped unit and those emitters or vice versa. Selective energizing of said emitters permits irradiation of selected areas of the wrapping only for maintaining the tensile strength of the wrapping at sharp corners and edges of the transport unit. Lamination of a folded top portion of the wrapping may be effected. An apparatus for carrying out the shrinking of the wrapping comprises a carrier for a plurality of heat radiation emitters and means for effecting the relative movement. Two forms are disclosed, one in which the emitter carrier is a vertically movable, horizontal frame and one in which the emitter carrier is in the form of gates through which the wrapped transport unit is carried by conveyors.
Inventors
👤 Olov Erland Gustavsson
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-30 09:12
CPC Classifications
B; B65; B65B; B65B53/00; B65B53/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
27 words
An apparatus according to claim 1, wherein said directional heat emitters are mounted on said mainly horizontal carrier frame in a manner to direct them obliquely downwards.
Claim 2
Dependent Claim
28 words
An apparatus according to claim 1, wherein said carrier frame forms a horizontal enclosure with four sides that forms an opening to be passed by said wrapped unit.
Claim 3
Independent Claim
107 words
A method of shrinking a wrapping of heat-shrinkable plastic sheet surrounding a transport unit comprising a collection of goods on a common load carrier, which comprises the steps of subjecting the unit with its plastic sheet wrapped to directed heat radiation from a plurality of directional heat-radiation emitters, selectively energizing and deenergizing said directional heat-radiation emitters to heat only limited portions of the plastic sheet wrapping of the transport unit while effecting a relative movement between said emitters and the wrapped unit and while directing said emitters towards portions of the plastic sheet wrapping which are located mainly along lines tranversing the direction of said relative movement.
Claim 4
Dependent Claim
22 words
An apparatus according to claim 1 that includes means for energizing and deenergizing selected groups of said plurality of heat radiation emitters.
Claim 5
Dependent Claim
30 words
An apparatus according to claim 1 which includes a carrier frame positioned adjacent each opposite side of said unit to heat the two opposite sides of said transport unit wrapper.
Claim 6
Independent Claim
190 words
An apparatus for shrinking a wrapper of heat-shrinkable plastic sheet material surrounding a transport unit, comprising a transport track for said wrapped unit, said transport track being composed of two portions along the first of which the wrapped unit is caused to move in one direction along one axis of the unit and along the second of which the wrapped unit is caused to move in another direction along a second axis of the transport unit mainly perpendicular to said first axis, a first pair of emitter carrier frames each having a main extension in a vertical direction and being positioned on opposite sides of said first track portion, a second pair of emitter carrier frames each having a main extension in a vertical direction and being positioned on opposite sides of said second track portion, a plurality of directional heat radiation emitters mounted on each of said carrier frames in position to direct radiant heat towards opposite sides of the wrapped unit passing therethrough, whereby the plastic sheet wrapping of the transport unit is first heated on two opposite sides thereof and subsequently on the two remaining sides thereof.
Claim 7
Dependent Claim
28 words
An apparatus according to claim 7, wherein said heat radiation emitters mounted on said first and second frameworks are capable of being energized and deenergized in selected groups.