Package making – Methods – With contents treating
Reexamination Certificate
2003-04-21
2004-11-02
Gerrity, Stephen F. (Department: 3721)
Package making
Methods
With contents treating
C053S114000, C053S119000, C053S439000, C053S529000
Reexamination Certificate
active
06810643
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the packaging of compressible materials such as foam, spring assemblies, mattresses and the like, and is more particularly directed to method of roll packing such compressible materials.
BACKGROUND OF THE INVENTION
Conventional packaging and transportation of compressible materials such as finished mattresses, as well as foam or spring assemblies used in the manufacture of mattress products, generally involves handling of the materials in an uncompressed state. As such, the shipping and storage of the materials requires much more space than would be required if the materials were provided in a compressed state. To improve the efficiency of shipping and storage, foam mattress cores have been packaged in a compressed state by flattening the foam and sealing it in an evacuated bag. See, for example, U.S. Pat. No. 4,711,067 to Magni. This method of packaging foam cores, however, is not useful in packaging spring assemblies. In addition, storage and transportation efficiencies of the foam could be further improved by packaging the flattened cores into a tight roll.
Roll packing generally involves winding-up a desired material to form a roll and then securing the roll to prevent uncoiling of the roll during handling. In the case of compressible materials such as mattresses and foam or spring cores, it is often desired to compress the materials during the roll packing process to obtain a more dense and compact roll. Various devices have been used to achieve compression of roll packed materials. U.S. Pat. No. 3,927,504 to Forrister discloses an apparatus for rolling resilient foamed sheet material without the use of a mandrel. This machine is not useful for packaging spring assemblies and does not have the capability to package multiple units of a compressible material into a large roll. The device further does not provide for packaging a compressible material with a barrier layer between successive turns of the roll, which barrier layer is desirable to prevent adhesion between successive layers of foam.
Some roll packing systems include a mandrel for facilitating the winding of the material. For example, U.S. Pat. No. 2,114,008 to Wunderlich discloses a spring packing machine having a radially collapsible arbor for use in roll packing spring assemblies. A barrier layer between successive turns of the roll keeps the spring assemblies separate and permits easy removal of a single assembly from the roll. However, this machine is not useful for roll packing foam material due to the presence of a pressure bar which would tend to snag a compressed foam as it passed beneath. The disclosed machine also has other drawbacks. For example, to remove a finished roll, the arbor must be removed from the machine and collars must be adjusted to collapse the arbor so that the roll can be taken off the arbor. The arbor must then be replaced in the machine before another roll can be formed. Operation of the machine is thus very labor intensive and ergonomically inefficient.
The roll packing of spring assemblies, foam cores or other compressible materials onto mandrels has heretofore been a problem because the compressible material does not slide easily off of the mandrel after being rolled up. Difficulties in removing the compressible material from the mandrel are due to the material's high friction coefficient in combination with the high compression force against the mandrel that is created when the compressed material is wound around the mandrel. When a spring or foam core is compressed onto a mandrel, the material has a natural tendency to want to expand in both radial directions, i.e., to expand radially outward from the mandrel and radially inward to the mandrel. As a result of the inward compressive force, the compressible material essentially sticks to the mandrel.
Consequently, attempting to withdraw the roll from the mandrel may damage the first few layers of the roll or cause undesirable telescoping or tearing of the rolled material as it is removed from the mandrel. Additionally, the center of the roll may implode once the roll is removed from the mandrel, causing the layers proximate the center of the roll to deform or tear.
There is thus a need for a method of efficiently roll packing compressible material such as foam or spring cores so that the roll may removed from the mandrel without damaging the rolled material or causing undesirable telescoping or tearing of the rolled material.
SUMMARY OF THE INVENTION
The present invention provides a method of roll packing a variety of compressible materials such as foam cores, spring assemblies, and fiber materials used in the manufacture of bedding or seating products, as well as finished mattresses. The machine preferably has a rotatable mandrel with collapsible cleats which permits finished roll packed materials to be easily removed from the machine by sliding the roll off of the mandrel. This type of mandrel, when used in conjunction with the present invention, permits rolled materials to be removed without any telescoping or tearing of the materials which is usually caused by binding of the roll packed material on the mandrel. However, the methods of the present invention may be used with other types of mandrel including those without retractable cleats. The present invention is especially useful in roll packing foam materials which are highly susceptible to binding against a mandrel. The methods of the present invention further permit roll packing practically any compressible material, even materials as diverse as coiled spring assemblies for mattresses and foam cores.
In accordance with the present invention, a method is provided which employs a mandrel having collapsible cleats for winding compressible materials to be roll packed. A feed table may be provided upstream of the mandrel to support and direct the compressible material to the mandrel. At least one compression roller associated with the mandrel is used to compress in-fed compressible materials in a nip between the compression roller and the mandrel as the material is being wound upon the mandrel. At least one compression roller is adjustable to vary the spacing between the mandrel and the compression roller so that the amount of compression for the in-fed materials can be varied accordingly. The apparatus used to practice of the present invention may be identical to or similar to the apparatus disclosed in applicant's U.S. patent application Ser. No. 10/066,905, filed on Oct. 22, 2001 entitled APPARATUS AND METHOD FOR ROLL PACKING COMPRESSIBLE MATERIALS, which is fully incorporated by reference herein. However, any other apparatus may be used to practice the present invention. The invention of this application is not intended to limit the apparatus used to employ the methods of the present invention.
In further accordance with the present invention, a method for roll packing various compressible materials includes the steps of providing a mandrel rotatable about an axis and a compression roller, directing in-fed compressible materials between the mandrel and compression roller, adjusting the spacing between the mandrel and compression roller, winding the compressible material around the mandrel, stopping the mandrel when a desired amount of in-fed material has been wound upon the mandrel, and removing the roll packed material from the mandrel.
According to one aspect of the present invention, roll packing material such as paper is wrapped around the mandrel before a sheet of corrugated material is fed to the mandrel. Rotation of the mandrel winds the corrugated material around the mandrel at least one revolution. The corrugated material is then secured to itself to form a corrugated sleeve or core around the mandrel. Preferably, the corrugations of the corrugated material are oriented generally perpendicular to the rotational axis of the mandrel. A compressible material such as a continuous web of foam or other compressible material or a series of spring assemblies is fed to the mandrel along with the roll packing materi
Gecic Josip
Mossbeck Niels S.
Wells Thomas J.
Gerrity Stephen F.
L&P Property Management Company
Truong Thanh
Wood Herron & Evans LLP
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