US 4,505,092 A · Package sensing/film control system for film wrapping machine

Abstract

A package sensing system provides length, width and height signals to a film control system which selects the width and length of stretch film to be used by a film wrapping machine to wrap the sensed package. Package width is sensed by spring biased swing arms which active electrical switches upon deflection by an entering package. A wide package is indicated if both swing arms are deflected. The length and height of a package are sensed by a generally vertical downwardly extending lever arm which is pivotally mounted above the package entryway into the machine. A first electrical switch coupled to the lever arm generates a length signal upon initial contact by an entering package and a second electrical switch coupled to the lever arm generates a height signal depending upon the ultimate deflection of the lever arm by the package. Two film widths are provided with the narrower of the two being selected for packages which activate neither the width sensing system or the height sensing system and the wider of the two films being selected upon activation of either of those sensing systems. The length of the film drawn is determined by the length of a measured package with that length being incrementally increased if a high package is sensed.

Claims18

Dependent claims

In a film wrapping machine including at least a wide roll and a narrow roll of continuous stretchable film, gripper means for drawing a section of one of said rolls of film into said machine, means for selectively presenting any one of said rolls of film to said gripper means, and means for controlling the stroke of said gripper means to determine the length of said section of film drawn into said machine, an improved package sensing and film control system comprising:

lateral sensing means for generating a wide package signal and a narrow package signal representative of the width of a package entering said machine;
longitudinal sensing means for generating signals representative of the length of a package entering said machine;
vertical sensing means for generating a low package signal and a high package signal representative of the height of a package entering said machine;
and
control means responsive to said length signals, said width signals and said height signals for controlling said presenting means and said gripper controlling means to select both the width and length of the section of stretchable film drawn into said machine said control means interpreting said length signals as being one of a plurality of package lengths and responding to said package size signals to present the narrow film roll to said gripper means unless a wide package signal or a high package signal is received, in which case the wide film roll is presented and for controlling said gripper controlling means to draw the length of film indicated by said length sensing means with the next longer film length being drawn if a high package signal is received unless the maximum or minimum film length was initially indicated.

2 more elements

In a film wrapping machine including control means for selecting both the width and the length of a section of stretchable film drawn from one of at least two differing width continuous rolls of such film in response to signals characteristic of a package to be wrapped, an improved package sensing system for generating said signals comprising:

lateral sensing means for sensing the width of a package as it is fed into the machine and comprising:
first sensing means on one side of the package entryway to the machine;
and
second sensing means on the opposite side of the package entryway to the machine whereby narrow packages to be wrapped will engage neither or one of said first and second sensing means and wide packages will engage both of said first and second sensing means upon entering the machine;
longitudinal sensing means for sensing the length of a package as it is fed into the machine;
and
vertical sensing means for sensing the height of a package as it is fed into the machine to determine whether the height of a package is less than or greater than a predetermined height, said control means basing the length of said film section on the sensed length of a package unless said predetermined height is exceeded in which case the length of said film section is increased.

4 more elements

In a film wrapping machine including a source of continuous stretchable film, gripper means for drawing a section of said film into said machine, and film length selection means for setting the stroke of said gripper means to determine the length of said film section, an improved package sensing and film control system comprising:

longitudinal sensing means for measuring the length of a package entering said machine;
vertical sensing means for measuring the height of a package entering said machine to determine whether the package is higher than a predetermined height dimension;
and
control means for monitoring said longitudinal and vertical sensing means and for controlling said film length selection means to draw one of a plurality of film lengths in accordance with the measured package length for packages which do not exceed said predetermined height dimension and to draw the next longer film length for packages which do exceed said predetermined height dimension.

1 more element

A method of selecting the size of a sheet of wrapping material to be used for wrapping a package comprising the steps of:

transporting the package toward a wrapping station;
measuring the package length as it is being transported;
measuring the package height as it is being transported to determine whether the package height is greater than a predetermined height dimension;
providing a continuous supply of wrapping material wider than said package with a leading edge thereof positioned at a defined material pulling location;
pulling the leading edge of said wrapping material to a first location determined in accordance with the measured length of said package if the measured height of the package does not exceed said predetermined height dimension and to a second location a defined distance beyond said first location if the measured height of the package exceeds said predetermined height dimension.

2 more elements

A method of wrapping a package comprising the steps of:

transporting the package horizontally to an elevator platform;
measuring the package length as it is being transported to said elevator platform;
measuring the package height as it is being transported to said elevator platform to determine whether the height is greater than a predetermined height dimension;
providing a continuous supply of stretch wrapping film wider than said package with a leading edge thereof positioned above said elevator platform at a film pulling location;
pulling the leading edge of the film in a horizontal plane to extend a length of the film over said package;
pulling the leading edge of the film to a first location determined in accordance with the measured length of said package if the measured height of the package does not exceed said predetermined height dimension and to a second location a defined distance beyond said first location if the measured height of the package exceeds said predetermined height dimension;
severing the film from said supply to create a rectangular sheet of said film;
elevating the package into stretching engagement with said sheet;
tucking the former leading edge and the side edges of said sheet beneath said package;
conveying the package from the elevated level to tuck the trailing edge of the sheet beneath said package;
and
sealing the sheet of film beneath the package to secure the sheet therearound.

9 more elements

Dependencies are inferred from the claim text.

Package sensing/film control system for film wrapping machine

Life of this patent

Package sensing/film control system for film wrapping machine

Life of this patent

Abstract

Claims18