Abstract:
A method of packaging spring units in which first and second webs of insulator material are fixedly located against the top and bottom surfaces of the spring units. The webs are folded around outermost coil springs along longitudinal edges of the spring units. The reverse sides of the webs are glued, welded or otherwise permanently secured together. In another embodiment, side portions of the webs are secured together, sandwiching the spring units therebetween. The resultant bedding products are then roll-packed.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This patent application is a continuation application of U.S. patent application Ser. No. 09/397,337 filed Sep. 15, 1999 entitled METHOD OF PACKAGING SPRINGS AND RESULTING PACKAGED PRODUCT, which is fully incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the packaging of spring units. More specifically, this invention relates to a method of roll-packing plural spring units. 
     BACKGROUND OF THE INVENTION 
     It is known in the art to pack spring units for use in making mattresses by winding a length of flexible web material, e.g., disposable paper or re-usable hessian around a mandrel and feeding the spring units successively into the nip between the growing roll and the traveling web material. The spring units are compressed as they are drawn into the roll, and the result is that the roll-packed springs have a much reduced volume as compared to conventionally stacked spring units. 
     One type of machine known for this purpose has a winding mandrel to which a holding bar is bolted by its ends for holding the leading end of a packing web material. An upwardly moveable pressure roller is mounted above the mandrel so as to define therewith an entry nip for the web material. The web material is fed from a reel supported at the rear of the machine over the pressure roller and on to the mandrel. An operator standing at the front of the machine feeds springs into the entry nip. 
     Another machine for packing bedding springs is seen in U.S. Pat. No. 4,669,247. This patent describes packing spring units into a roll with a web of paper or other reusable material. A similar spring packing machine is seen in U.S. Pat. No. 2,114,008, in which a roll of wrapping paper is fed along a table and into a wrapping mechanism whereat spring assemblies are placed upon the paper and fed into the machine by the paper movement. 
     All of these prior art machines compress and wrap springs in a single web of paper or reusable material which separates the multiple layers of spring units in a roll and maintains the springs in a compressed state for shipment from a spring manufacturer to a mattress manufacturer. This conventional roll-packing technique tends to be expensive. Either large amounts of paper that will be eventually disposed of are used to wrap springs at a cost to the spring manufacturer which is often passed on to the mattress manufacturer, or much more expensive recyclable packaging is used to roll and ship springs. The recyclable material which is used to roll and ship springs must be thereafter shipped back to the spring manufacturer who, again, may incur the cost of shipping back the material and may pass that expense on to the mattress manufacturer. In addition, recyclable spring packaging material has a relatively short life span, albeit longer than paper packaging. 
     Therefore, it has been one objective of the present invention to reduce the cost of packaging and shipment of spring units. 
     It has been another objective of the present invention to provide a method of packaging spring units without using conventional paper or reusable packaging methods. 
     It has been a further objective of the present invention to provide a method of packaging a spring unit in which the spring unit is packaged in insulator material that will not be disposed of but, rather, be used by the mattress manufacturer in mattress production. 
     SUMMARY OF THE INVENTION 
     The preferred embodiments of the present invention accomplish these objectives with a method of packaging a resilient spring unit such as a plurality of interconnected coil springs in which first and second webs of spring insulator material are first attached to the spring unit so as to be located against the spring unit top and bottom surfaces and thereafter roll-packed for shipment from a spring manufacturer to a mattress manufacturer who simply unrolls the spring units and cuts the insulator material between the spring units, the spring units having the insulator material attached thereto to be used in mattress manufacture so as to eliminate the need to roll-pack the spring units with disposable paper or expensive reusable material. 
     The spring unit has a uniform depth defined by a generally planar top first surface and a parallel generally planar bottom second surface. The spring unit has a longitudinal dimension or length defined by a pair of opposed parallel end surfaces and a transverse dimension or width defined by a pair of opposed parallel side surfaces. The longitudinal dimension or length is generally greater than the transverse dimension or width of the spring unit as in most bedding products. However, a square spring unit in which the longitudinal and transverse dimensions are equal may also be packaged using this inventive method. 
     The method of the present invention comprises providing first and second web rolls of insulator material spaced from one another. The first web roll comprises a first web of spring insulator material, e.g., woven or non-woven material, wound about a core. Similarly, the second web roll comprises a second web of spring insulator material wound about a core. 
     Each of the first and second webs of insulator material have a pair of opposed side edges defining a width of the web which is wider than the spring unit&#39;s transverse dimension. Each web across its width has a pair of opposed side portions and a central portion between the side portions. 
     The first web of insulator material is passed over and located against the first surface of the spring unit, and the second web is passed under and located against the second surface of the spring unit. The longitudinal dimension of the spring unit is generally parallel to the opposed side edges of the first and second webs which are generally parallel to one another. 
     In a first preferred embodiment, the first and second webs are folded back upon themselves around the top and bottom turns of the edgemost coil springs of the spring unit so that the opposed side portions are located against the surface of the central portion located against the spring unit. These side portions are then bonded, welded or otherwise secured to the central portion. In a second preferred embodiment, the side portions of the first web are bonded or welded to the adjacent side portions of the second web so as to form a tight fitting sleeve in which the spring unit is securely located. The spring unit with the first and second webs secured there against constitutes a bedding product. 
     The final step in the method of the present invention is to draw the bedding product into a roll-packing machine in which the bedding product is compressed and rolled onto a dowel whereafter the bedding product is maintained in this rolled and compressed state for shipment to a mattress manufacturer. 
     These and other objectives and advantages of this invention will be readily apparent from the following description of the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first preferred embodiment of the present inventive method of packaging a resilient spring unit; 
     FIG. 1A is a cross-sectional view taken along line  1 A— 1 A of FIG. 1; 
     FIG. 2 is a side view of a bedding product being roll-packed; 
     FIG. 3 is a perspective view of a second preferred embodiment of the present inventive method; and 
     FIG. 3A is a cross-sectional view taken along line  3 A— 3 A of FIG.  3 . 
     FIG. 4 is a flow chart of a portion of the method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As can be seen generally in FIGS. 1,  1 A,  3 ,  3 A, a spring unit  10  generally has a top or first surface  12  and a bottom or second surface  14 . The spring unit  10  has a length or a longitudinal dimension L and a width or a transverse dimension D, the longitudinal dimension L being generally larger than the transverse dimension D. However, it will be appreciated by those in the art that L may be substantially similar to D in dimension. The spring unit  10  has a thickness T between the first surface  12  and the second surface  14  which defines opposing end surfaces  16   a ,  16   b  and opposing side surfaces  18   a ,  18   b.    
     The spring unit  10  is generally comprised of a plurality of coil springs  20 , the coil springs  20  being secured one to another by means generally known in the art. Each coil spring  20  has a top turn  22  comprising a portion of the first surface  12  and a bottom turn  24  comprising a portion of the second surface  14 . 
     The first surface  12  and the second surface  14  are covered with first and second webs  26 ,  28 , respectively, of insulator material. The insulator material used to cover the first and second surfaces  12 ,  14  of the spring unit  10  is generally a woven or non-woven material. Each of the first and second webs  26 ,  28  have an obverse side or outer surface  30  and a reverse or inner surface  32 , the or inner surface  32  of each of the first and second webs  26 ,  28  being located against the first and second surfaces  12 ,  14  of the spring unit  10 , respectively. 
     As seen in FIGS. 1A and 3A, each of the first and second webs  20   26 ,  28  has a center portion  34  and opposed side portions  36 ,  38 . Each of the first and second webs  26 ,  28  has a substantially similar width W larger than the transverse dimension D of the spring unit  10  so that the opposed side portions  36 ,  38  generally extend beyond the transverse dimension D of the spring unit  10  in substantially equal amounts. The lengths (not indicated) of the first and second webs  26 ,  28  are considerably longer than the longitudinal dimension L of a single spring unit  10  so that plural spring units  10  may be packaged by the inventive method described in further detail below. 
     In the present inventive method of packaging a spring unit  10 , the first and second webs  26 ,  28  are carried upon respective first and second cores  40 ,  42  which allow the first and second webs  26 ,  28  to be drawn therefrom in reverse directions as indicated by directional arrows  40   a ,  42   a . The first and second webs  26 ,  28  are drawn between respective first and second guide rollers  44 ,  46 , the rollers  44 ,  46  being spaced apart from each other so that spring unit  10  may be received therebetween. A conveyor  48  transports the spring unit  10  by directional arrow  48   a  into a space  50  defined between the first and second rollers  44 ,  46  whereat the first and second webs  26 ,  28  are passed over and under and located against the first and second surfaces  12 ,  14 , respectively, of the spring unit  10 . 
     In a first preferred embodiment, after the first and second webs  26 ,  28  are located against the respective first and second surfaces  12 ,  14  of the spring unit  10 , an adhesive unit  52  deposits adhesive  56  upon the inner surface  32  of the side portions  36 ,  38  of each of the first and second webs  26 ,  28 . The spring unit  10  having the first and second webs  26 ,  28  located there against is then passed to a folding unit  54  which folds the reverse side  32  of the side portions  36 ,  38  of each of the first and second webs  26 ,  28  with the adhesive  56  deposited thereon against the reverse side  32  of the respective center portion  34  and against the top and bottom turns  22 ,  24  of the coil springs  20  comprising the longitudinal margins of the spring unit  10 . 
     As seen in FIGS. 3 and 3A, in a second preferred embodiment, after the first and second webs  26 ,  28  are located against respective first and second surfaces  12 ,  14  of the spring unit  10 , the spring unit  10  with the first and second webs  26 ,  28  located there against is passed to a welding unit  58  whereat the reverse sides  32  of the opposed side portions  36  of the first web  26  are welded to the adjacent side portions  36  of the second web  28 . While only side portions  36  of the first and second webs  26 ,  28  are shown in FIG. 3A, it will be understood that side portions  38  are a mirror image thereof and are welded in a similar manner. The welding together of the first and second webs  26 ,  28  may be accomplished by any suitable welding process for woven or non-woven materials known in the art, e.g., ultrasonic or radio frequency welding, to create a weld  58   a , as seen in FIG.  3 A. 
     After the first and second webs  26 ,  28  have been fixedly located against the first and second surfaces  12 ,  14  of the spring unit  10  by either the gluing or the welding methods as described above, the spring unit  10  with the first and second webs  26 ,  28  located there against is then passed to a roll-packing machine  60  as best seen in FIG.  2 . The roll-packing machine  60  has a plurality of rollers  62  which carry thereon an endless belt  64  traveling in a direction indicated by directional arrow  64 a. The spring unit  10  with the first and second webs  26 ,  28  attached permanently thereto comprises a bedding or seating product  68  ready for shipment, for example, from a spring manufacturer to a mattress or seat manufacturer. As the product  68  is wound about a core  70  upon which it is to be transported, the roll-packing machine  60  compresses the bedding or seating product  68  so that plural bedding or seating products  68  may be so packaged. 
     When the packaged roll of bedding or seating units  68  arrive at the mattress or seat manufacturer&#39;s facility, all that the manufacturer need do is unroll the packaged products from the roll and transversely cut the webs  26 ,  28  at locations between the spaced spring units  10 . The resulting bedding or seating product  68  having the insulator material permanently secured to its top and bottom sides is than ready for application of the appropriate padding and upholstery materials to complete the mattress or seat. 
     From the above disclosure of the detailed description of the present invention and the preceding summary of the preferred embodiment, those skilled in the art will comprehend the various modifications to which the present invention is susceptible. Therefore, I desire to be limited only by the scope of the following claims and equivalents thereof.