US 4,712,354 AGranted

Dual rotating stretch wrapping apparatus and process

AssigneeLantech, Inc.

InventorsPatrick R. Lancaster, William G. Lancaster

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Abstract

A novel apparatus and process for high speed continuous film web wrapping of uniform loads, in which a first wrap is applied in a first direction transverse to the path of the moving load and a second wrap is applied in a second direction opposite the first direction. This dual wrap nullifies the disabling effects of helical wrap bias when a single wrap is applied at high speed to a moving load, and produces a longitudinal containment force after film web recovery over time on leading and trailing ends of the load. In the apparatus two wrapping stations are provided together with a wrapping conveyor assembly which carries the film web wrapped around the load and conveyor through the two stations. Each station includes a dispensing ring on which a film roll and an elongation mechanism are mounted, a drive motor to rotate the ring and means to drive the elongation mechanism to draw film web from the roll and stretch the same beyond its yield point at ambient temperature on its path from the roll to the load and conveyor. The regulation of elongation in the elongation mechanism and the regulation of film supply speed from the elongation mechanism are independent of film demand speed at the load.

Claims33

Dependent claims

An apparatus for wrapping a load to contain the load comprising:

wrapping conveyor means for conveying the load and a wrapped web in a longitudinal direction relative to first and second film dispensing means;
said first film dispensing means having means for stretching and wrapping a first web around the load and onto at least part of the wrapping conveyor means, means for rotating said first dispensing means in a first circumferential direction around the load while the load is conveyed in the longitudinal direction relative to the first film dispensing means to form a first helical layer which is formed and biased in a first helical direction;
said second film dispensing means having means for stretching and wrapping a second web around the load and onto the first helical layer of web, means for rotating said second dispensing means in a second circumferential direction around the load opposite the first circumferential direction while the load is conveyed in the longitudinal direction relative to the second film dispensing means to form a second helical layer which is formed and biased in a second helical direction opposite the first helical direction, and for producing in combination with the first helical layer a containment force on the wrapped conveyor means having longitudinal and circumferential components without a substantial helical component, at least one of the longitudinal and circumferential components being substantial;
and
means for transferring the first and second helical layers as a unit from the wrapping conveyor means onto the load to apply a containment force on the load having longitudinal and circumferential components without a substantial helical component, at least one of the longitudinal and circumferential components being substantial.

2 more elements

A method for wrapping a load to contain the load comprising:

conveying the load in a longitudinal direction on a wrapping conveyor relative to first and second wrapping means;
rotating a first web around the load in a first circumferential direction and, stretching and wrapping the first web around the load and onto at least part of the wrapping conveyor in the first circumferential direction with said first wrapping means during said conveying step to form a first helical layer which is formed and biased in a first helical direction;
rotating a second web around the load in a second circumferential direction opposite the first circumferential direction and, stretching and wrapping the second web around the load and onto the first helical layer of web in the second circumferential direction opposite the first circumferential direction with said second wrapping means during said conveying step to form a second helical layer which is formed and biased in a second helical direction opposite the first helical direction, and producing in combination with the first helical layer a containment force on the wrapped conveyor having longitudinal and circumferential components without a substantial helical component, at least one of the longitudinal and circumferential components being substantial;
and
conveying both the load and the wrapped webs on the wrapping conveyor in a longitudinal direction and transferring the first and second helical web layers as a unit from the wrapping conveyor onto the load to apply a containment force on the load having longitudinal and circumferential components without a substantial helical component, at least one of the longitudinal and circumferential components being substantial.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/903,896Filed 4 Sep 1986 · continuation
Priority: 23 Feb 1984
Granted: 15 Dec 1987
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

B65B 11/008
Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material: by webs…
B65B 11/58
Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material: applying two…
B65B 2210/18
Details of wrapping machines with web dispensers for application of a continuous web in layers onto the articles: the web dispenser being mounted…
B65B
Machines, apparatus or devices for, or methods of, packaging articles or materials