Plastic and nonmetallic article shaping or treating: processes – Direct application of electrical or wave energy to work – Radio frequency
Reexamination Certificate
2001-03-20
2003-10-07
Ball, Michael W. (Department: 1733)
Plastic and nonmetallic article shaping or treating: processes
Direct application of electrical or wave energy to work
Radio frequency
C264S479000, C264S505000, C016S225000, C016S372000, C029S011000, C160S231100, C160S231200, C156S219000, C156S272200, C156S273700
Reexamination Certificate
active
06630094
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to flexible hinged structures, and particularly to flexible hinged structures which are placed between a pair of substantially rigid panels so that the panels may be hinged one to the other. The panels are formed of a substantially rigid material such as rigid polyvinyl chloride, and the hinge is formed of a flexible plastics material such as polyvinyl chloride. The hinge is configured, however, so as to be resistant to rips or tears, so that the pair of substantially rigid panels to which the flexible hinge has been sealed may be hingedly moved one with respect of the other with impunity.
BACKGROUND OF THE INVENTION
A co-pending application Ser. No. 09/789,807, filed Feb. 22, 2001, in the names of the inventors herein, teaches a structure which may be fitted to the front edges of shelves and the like, and to which a plurality of substantially rigid plastic pockets may be placed so as to provide pricing or other information with respect to items being displayed on the shelves. Typically, such structure is found in retail stores an the like, in association with household articles and other articles of all kinds, where the retailer wishes to provide pricing information, product specifications, etc.
In order to do so, the co-pending application teaches the structure whereby a plurality of like pockets may be fixed to the display structure on the front of the shelf, and the co-pending application notes that the pockets may be hinged one to another, or hinged directly to the display structure.
When the display pockets are hinged one to another, it is necessary that they shall be secured one to another by a flexible hinge which is sealed to each of the substantially rigid pockets or panels. However, at least two further criteria exist.
The first criterium is that the flexible hinge which secures the substantially rigid panels one to the other must not only be flexible, it must be strong and resistant to ripping or tearing. Unfortunately, soft and flexible plastics material is not, in and of itself, sufficiently resistant to ripping or tearing, and thus the use of soft and flexible plastics material as a hinge structure has not been recommended, until development of the present invention.
The other criterium is that, when in their rest position, the two substantially rigid panels to which the flexible hinge has been sealed should be contiguous one to the other, in back face to front face relationship of the one to the other. This requires that the flexible hinge that is between the substantially rigid panels shall have sufficient elastic memory that the panels will assume the contiguous, face-to-face relationship unless they are being held apart by a user who has hingedly moved one panel with respect to the other so as to view the additional information which is on the back face of one panel or the front face of the other panel which were previously hidden from view.
Thus, the need for a tear-resistant but flexible hinge structure arises. In response thereto, the present inventors have unexpectedly discovered that if a flexible plastic sheet material is reshaped over at least a selected portion thereof so as to provide a structure which essentially comprises a plurality of contiguous webs and ribs, or flat portions and raised portions, which are arranged in a staggered relationship, it is extremely difficult to rip or tear the flexible hinge structure beyond the discontinuity in the configuration of the flexible hinge structure. Thus, a rip or tear which has somehow been cause—such as by cutting—in the flexible hinge structure will not propagate along its length or across its width.
SUMMARY OF THE INVENTION
To that end, the present invention provides a tear-resistant, flexible hinge structure for placement between a pair of substantially rigid panels, wherein the flexible hinge structure is made from a flexible plastics sheet material having a first softening temperature, a second elastic memory loss temperature, and a third melting temperature. Of course, the second elastic memory loss temperature is higher than the softening temperature and lower than the melting temperature.
The flexible hinge structure is formed under heat and pressure in the flexible sheet material so as to comprise at least three parallel rows of alternating flat and raised portions, in staggered relationship. That configuration is such that each flat portion is contiguous to 2, 3, or 4 raised portions; and each raised portion is contiguous to 2, 3, or 4 flat portions.
The flexible hinge structure has opposed sides which are sealed one to each of the pair of substantially rigid panels.
The present invention is such that each of the alternating flat and raised portions in each row thereof has a width which is substantially equal to the width of all other flat and raised portions of that row.
Also, the length of each of the flat portions of each of the rows of alternating flat and raised portions is substantially equal to the length of all other flat portions; and likewise, the length of each of the raised portions of each of the rows of alternating flat and raised portions is substantially equal to the length of all the other raised portions.
The flat and raised portions of each row thereof are offset by one-half the length of a flat portion of each row, with respect to the flat and raised portions of each adjacent row thereof.
The thickness of each raised portion of the flexible hinge material, when the flexible hinge has been formed, is greater than the thickness of each flat portion of the flexible hinge material.
Typically, the flexible sheet material is polyvinyl chloride.
The plastic sheet material typically has an initial thickness in the range of 0.010 to 0.025 inches.
The width of each row is in the range of 0.050 to 0.075 inches; and the pitch of one flat portion and one raised portion is typically in the range of 0.0115 to 0.250 inches.
The softening temperature at which the sheet plastics material starts to lose its shape memory and starts to become flexible, is in the range of 175° F. to 200° F.
The full melting temperature at which the sheet plastics material has fully liquidized is in the range of 275° F. to 350° F.
The elastic loss memory at which the sheet plastics material has fully lost its elastic memory is in the range of 250° F. to 270° F.
In general, the flexible hinge structure of the present invention has been formed flat, but is re-formed and cooled in a semi-circular configuration crosswise of the flexible hinge structure.
Typically, there are between three and seven rows of alternating flat and raised portions, usually five rows.
Also, the hinge structure is generally sealed to the substantially rigid panels using radio frequency energy, and pressure, to each of the substantially rigid panels.
The present invention provides a method of making a tear-resistant, flexible hinge structure as described above. The method comprises the following steps:
a) a hard, flat metallic platen is provided.
b) a heat resistant, non-conductive barrier sheet is placed on the platen.
c) a metallic conductive die is provided, where the die has at least three parallel rows of alternating projections and intervening depressions therebetween. The rows of alternating projections and intervening depressions are arranged in staggered relationship, whereby each projection is contiguous to 2, 3, or 4 depressions, and each depression is contiguous to 2, 3, or 4 projections.
d) a pressure producing structure is provided over the metallic platen, together with control means for the pressure producing structure to advance the pressure producing structure towards the metallic platen, and to withdraw the pressure producing structure away from the metallic platen.
e) the metallic conductive die is secured to the pressure producing structure.
f) heating means are provided to heat the metallic conductive die to a predetermined temperature when it is in place on the pressure producing structure.
g) a source of radio frequency energy is provided, and it is connected betwe
Abramson Brian
Ferguson Steven
(Marks & Clerk)
Ball Michael W.
Goff John L.
Vidpro International, Inc.
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