Patent Abstract:
A fluorescent lamp or similary shaped fragile article is frictionally locked with a protective open-ended wrapper of tubular sleeve-like configuration by an inturned tab that constitutes a hinged part of the wrapper and is sandwiched between the inserted lamp and the wrapper wall. The wrapper is preferably fabricated from single-face corrugated paper and the tab is swingable about a hinge line such that the corrugations of the inturned tab extend transversely with respect to and thus do not nest with the corrugations of the wrapper, thereby enhancing the effectiveness of the tab as an integral article-retaining means.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of application Ser. No. 182,622, filed Sept. 22, 1971. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the art of packaging fragile articles and has particular reference to an improved paper wrapper for protectively packaging fluorescent lamps, and to the improved package which the wrapper provides. 
     2. Description of the Prior Art 
     As is well-known in the art, fluorescent lamps are generally protected from breakage during shipment and handling by an open-ended wrapper or sleeve or corrugated paper that is slipped over the lamp in the factory before the lamps are loaded into the shipping cartons. Such wrappers have four walls, are either square or rectangular in cross-section and, in either case, are dimensioned to effect a snug fit with the lamp envelopes and thus be frictionally locked in place. A wrapper of this type having paired walls of unequal width which define a rectangular cross-sectioned compartment is described and claimed in U.S. Pat. No. 3,476,235 issued Nov. 4, 1969 to J. E. Mills et al. Cartons having inturned hinged elements that serve as separators for a pair of nested light bulbs or as spacer means for a single bulb or radio tube are disclosed in U.S. Pat. Nos. 2,654,472; 2,870,949; 3,053,431, and 3,355,011. 
     While the prior art &#34;slip-over&#34; wrapper prevented the fluorescent lamps from contacting one another and breaking during shipment, additional protection against the danger of the lamp additionally slipping out of the wrapper while being handled by store personnel or prospective customers at the retail level would be highly desirable and advantageous for obvious reasons. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention provides this added protection by increasing the amount of frictional interlock between the inserted lamp or other article and the wrapper in a simple, economical and practical manner. This is accomplished by modifying one of the wrapper walls in such a way that a segment of the wall is converted into an inwardly-displaceable hinged article-retaining tab. This tab is inturned into the wrapper compartment just before the tubular article is inserted and is thus sandwiched between the packaged article and the wall of the wrapper. The wall thickness of the wrapper is accordingly doubled at this location -- thereby greatly increasing the frictional grip of the wrapper on the inserted article and securely anchoring the latter in place. 
     In the case of fluorescent or other types of electric lamps, the wrappers or sleeves are fabricated from single-face corrugated paper and the hinged locking tab is cut or coined from the wrapper wall in such a fashion that it swings about a hinge line that extends transversely with regard to the corrugations on the inner surface of the wrapper. The corrugations of the inturned tab thus do not nest with but &#34;bridge&#34; those of the wrapper wall and the effective thickness of the wrapper in this region is proportionately increased. The improved wrapper thus has a &#34;built-in&#34; safeguard against accidental lamp slippage and breakage which is reliable and economical since it requires no additional packaging material and automatically achieves its objective upon being activated at the beginning of the packaging operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the invention will be obtained from the exemplary embodiments shown in the accompanying drawing, wherein: 
     FIG. 1 is a fragmentary perspective view of a fluorescent lamp package according to the invention, a corner of the tabbed wrapper being removed to show the position of the packed lamp; 
     FIG. 2 is an enlarged sectional view of the tabbed portion of the wrapper along line II--II of FIG. 1, the lamp being shown in phantom outline; 
     FIG. 3 is an enlarged cross-sectional view of the tabbed portion of the wrapper and associated segment of the inserted lamp; 
     FIG. 4 is an enlarged plan view of the tabbed part of the wrapper before the tab is displaced from the plane of the wrapper wall; 
     FIG. 5 is a fragmentary plan view of the corrugated-paper blank from which the wrapper shown in FIGS. 1-4 is manufactured, an optional second tab being shown in dotted outline at the opposite end of the blank; and 
     FIG. 6 is a sectional view similar to FIG. 2 showing an alternative embodiment wherein the integral locking tab of the present invention is employed with a lamp wrapper of rectangular cross-section. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the present invention can be used with equal advantage in protectively packaging various types of fragile articles and electric lamps (such as &#34;lumiline&#34; incandescent lamps) that have at least one segment which is substantially circular in cross-section, it is especially adapted for use with tubular fluorescent lamps and it has accordingly been so illustrated and will be so described. 
     As shown in FIG. 1, the lamp package P in accordance with the present invention consists of an open-ended paper wrapper or sleeve S that is slipped over and protectively encloses the fluorescent lamp L. The lamp L has the usual tubular glass envelope 12 of circular cross-section and is terminated at each end by a suitable base member 14 and pin terminals 16. The sleeve S is fabricated from single-face corrugated paper that is divided into four wall panels 18, 19, 20, and 21 by parallel score lines 22, 23 and 24 which (in conjunction with a glued paper strip 25) provide hinged joints that permit the sleeve S to be folded flat for bulk shipment from the supplier to the lamp manufacturer. The sleeve S preferably slightly exceeds the overall length of the lamp L so that the latter is completely disposed within the sleeve. 
     As will be noted in FIG. 1, the single-face corrugated paper stock from which the tubular sleeve S is made consists of the usual thin facing sheet 29 and a fluted sheet 30 that is glued to the face sheet and provides a series of spaced parallel corrugations 31 that extend along the inner surface of the sleeve at right angles to its longitudinal axis and that of the packed lamp L. 
     The desired tight frictional interlock between the inserted lamp L and the sleeve S is achieved in accordance with the present invention by an inturned hinged element such as an arcuate tab 26 that constitutes an integral part of one of the walls of the sleeve and is sandwiched between the lamp envelope 12 and the overlying adjoined part of the sleeve. 
     In the embodiment shown in FIG. 1, the inturned tab 26 is cut or &#34;coined&#34; from wall 19 of the sleeve S and is swingable along a hinge line H that is canted or skewed relative to the corrugations 31 of the sleeve S so that the corrugations 31&#39; of the inturned tab 26 extend in a transverse direction relative to the corrugations 31 of wall 19 which they contact. The corrugations 31&#39; of the inturned tab 26 accordingly do not nest with but bridge the corrugations 31 of the sleeve proper (as indicated by the phantom showing of the respective corrugations in FIG. 1), thus doubling the &#34;effective&#34; wall thickness of the sleeve S in this region and locally increasing its frictional &#34;grip&#34; on the lamp L. 
     The foregoing feature of the invention is shown more clearly in FIGS. 2 and 3. As will be noted in FIG. 2, the sleeve S according to this embodiment is of square cross-section and its walls 18-21 are so dimensioned that they are contiguous with and preferably effect a snug fit with the adjacent arcuate surfaces of the lamp L. As depicted in FIG. 3, the &#34;two-ply&#34; thickness of the sleeve S achieved by the inturned sandwiched tab 26 and the skewed non-nesting relationship of its corrugations 31&#39; and the corrugations 31 of the overlying portion of the sleeve wall 19 automatically provides a tight fit at that location which partly collapses the corrugations and produces a slight bulging of the sleeve wall. The lamp L is thus securely anchored within the sleeve S. 
     As will be noted in FIG. 4, the tab 26 is preferably coined from the wall panel 19 by a pair of cut lines 33 and 34 that have arcuate end portions which terminate short of one another to provide a holding nick 35. The opposite ends of cut lines 33, 34 are joined by another cut line 36 and an aligned cut-score line 37 which form the canted hinge line H of the tab 26 referred to above. 
     As a specific example, excellent results have been obtained in the case of a 40 watt fluorescent lamp having a T12 type envelope (approximately 38 mm. in diameter) by using a square cross-sectioned sleeve S formed of single-face corrugated paper that was approximately 3.2 millimeters thick and had wall and tab components of the following dimensions (the various letters indicating the respective dimensions shown in FIG. 4): 
     
                       TABLE I______________________________________Length (N) of hold-down nick                      2.4 mm.Radius of curvature (R) of tab end                      7.9 mm.Length (T) of straight of tab                      20.6 mm.Distance (V) from tab to side of wall                      6.4 mm.Width (W) of wall panel    38.9 mm.Length (X) of hinged part of tab                      19.0 mm.Length (Y) of base cut of tab                      9.5 mm.Offset (Z) of hinge relative to sleeve                      9.5 mm. corrugations______________________________________ 
    
     As illustrated in FIG. 5, the sleeve is preferably fabricated from a single piece or blank B of corrugated-paper stock that is suitably scored and cut automatically in accordance with well-known techniques to provide the hinged wall panels 18, 19, 20, 21 and tab 26 and also space the latter a predetermined distance inwardly from the end of the blank. As indicated in phantom, a second displaceable tab 32 can be provided at the other end of the blank B to permit the lamp L to be packed by inserting it into either end of the sleeve S. 
     As will be obvious to those skilled in the art, packaging of the lamps L in the factory is accomplished by merely erecting the collapsed sleeve S into its tubular form, pushing the tab 26 inwardly into the sleeve compartment (which forms an opening 28 in the sleeve as shown in FIG. 1), and then inserting the lamp L into that end of the sleeve S so that the lamp hits the inturned tab and swings in the same general direction as the longitudinal axis of the sleeve -- thus automatically sandwiching it between the lamp envelope 12 and the wall 19 of the sleeve. 
     The invention is not limited to protective wrappers or sleeves of square cross-section but can be used with sleeves of the type described in the aforementioned U.S. patent to J. E. Mills et al. which are rectangular in cross-section. A lamp package Pa having a modified sleeve Sa of this construction is shown in FIG. 6 and, as will be noted, the sleeve has four hinged walls 18a, 19a, 20a, and 21a that are so paired and dimensioned that the sleeve has a major inside dimension that is larger than the diameter of the packed lamp L and a minor inside dimension that is less than the lamp diameter. As here shown, the oppositely-disposed pair of walls 18a and 20a define the minor width dimension of the sleeve Sa and one of these walls (wall 18a in this particular embodiment) is provided with a hinged inturned tab 26a that is sandwiched between the packed lamp L and the overlying portion of the wall 18a. The pressured frictional interlock in this region of the sleeve S a is accordingly intensified and (as illustrated) produces a more pronounced bulge on that side of the sleeve than the bulge which is produced on the opposite side by virtue of the tight-fitting rectangular cross-sectional configuration of the sleeve.

Technology Classification (CPC): 8