Package making – Apparatus for contraction of cover by stretching or shrinking
Patent
1980-12-12
1983-06-14
Sipos, John
Package making
Apparatus for contraction of cover by stretching or shrinking
53587, 53211, B65B 1104
Patent
active
043875521
ABSTRACT:
A process and apparatus for pre-stretching a plastic film material above its yield point in a roller assembly comprising at least two rollers connected for rotation at different speeds during a load wrapping operation. The downstream roller is at least partially driven by the film web connected to a turntable while the upstream roller rotates at a predetermined speed slower than that of the downstream roller to induce film elongation between the rollers. The force on the film between the roller assembly and the load is reduced by a powered constant torque device connected to the rollers to bring the force to the load down to a level permitting the film elongation between the roller assembly and the load to be equal to (balanced) or less than the elongation incurred between the rollers. The force from the torque device required to bring elongation on the load in balance with the elongation between the rollers will be equal to the difference between the force required to elongate the film between closely spaced rollers and the force required to hold the elongation after the film leaves the rollers corrected for the mechanical advantage and friction of the pre-stretch device. Since the film has been stretched above its yield point, the relieving of stress from the film between the rollers and the load allows the film to retain a high degree of pre-stretch elongation.
REFERENCES:
patent: 2597041 (1952-05-01), Stokes
patent: 2757495 (1956-08-01), Reichel
patent: 2854697 (1958-10-01), Ryan
patent: 2914893 (1959-12-01), Berst
patent: 2995779 (1961-08-01), Winter
patent: 3048895 (1962-08-01), Bottomley
patent: 3052917 (1962-09-01), Horn
patent: 3052924 (1962-09-01), Ezrin
patent: 3068528 (1962-12-01), Owens
patent: 3104937 (1963-09-01), Wyckoff
patent: 3351697 (1967-11-01), Hufnagel
patent: 3608056 (1971-09-01), Nelson
patent: 3734994 (1973-05-01), Blecha
patent: 3748142 (1973-07-01), Greene
patent: 3786127 (1974-01-01), Peet
patent: 3796785 (1974-03-01), Rest
patent: 3807004 (1974-04-01), Anderson
patent: 3816886 (1974-06-01), Van Cappellen
patent: 3843761 (1974-10-01), Bierenbaum
patent: 3884748 (1975-05-01), Anderson
patent: 4017227 (1977-04-01), Schmidt
patent: 4076785 (1978-02-01), Schmidt
patent: 4116892 (1978-09-01), Schwarz
patent: 4302920 (1981-12-01), Lancaster
Lancaster Patrick R.
Lancaster William G.
Hale John S.
Lantech Inc.
Sipos John
LandOfFree
Wrapping apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wrapping apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wrapping apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-158242