Horizontal sleeve applicator and method

An apparatus and method are provided for enwrapping a horizontally oriented product in a sleeve. A sleeve is formed by opening a flat tubular film and cutting a selected length of tubing. The sleeve is further opened in a forming tube to a cross sectional shape comparable with the cross sectional shape of the product. The forming tube is moved from a receiving position to a discharge position and the sleeve is moved in a horizontal plane to enclose the axially aligned product carried on a horizontally oriented conveyor.

FIELD OF THE INVENTION

The present invention relates to the field of apparatus and methods for the application of tubular labels to products, and more particularly to such apparatus and methods adapted for use with the products in horizontal orientation.

BACKGROUND OF THE INVENTION

Tubular film12is drawn from a supply (seeFIG. 2, number40) in the direction indicated by arrow A, i.e. downstream, to pass a cutter14, of any known type selected according to the shear characteristics of the tubular film12material. Tubular film12is an extruded plastic resin, for example polyvinyl chloride (PVC) or high density polyethylene (HDPE). In the preferred embodiment, a cutter14comprises a fixed blade and a movable blade. The movable blade is moved along a linear path that is perpendicular to planes α and β, and the fixed blade resides at a slight angle to the moving blade. A cutter of this type is described in detail in U.S. patent application Ser. No. 10/411,717, owned by the assignee of this application, and incorporated herein by reference. Other forms of cutter, for example a single blade cutter or a hot wire cutter, are considered within the scope of the present invention.

As tubular film12is moved forward in the direction of arrow A, a forward portion of tubular film12is inserted into forming tube18afor a selected length beyond cutter14. Cutter14then severs the selected length of tubular film12from the supply of tubular film, creating sleeve22. The selected length of sleeve22is typically chosen to substantially equal the length of product24to be enwrapped thereby. In other applications, the length of sleeve22is selected to be shorter than the length of product24so as to enwrap a portion, not the entire length, of product24. When sleeve22has been severed from the supply of tubular film12, forming tube18ais moved downwardly to its second position at plane β with sleeve22residing therein, placing forming tube18bin axial alignment with product24. Product24is resting upon support links28of conveyor26. Product24is conveyed upon conveyor26in the direction indicated by arrow D. As shown, product24is relatively long and thin, for example a felt tip pen, and is best handled in horizontal orientation. Support links28are preferably formed with a tapered end29, residing closer to forming tube18bso as to reduce resistance to the assembly of sleeve22onto product24. It is to be understood that the stiffness and frictional characteristics of sleeve24affect the ease of assembly. When described below without regard to being at a level with either plane α or plane β in the apparatus, the forming tube will be designated as forming tube18. In the preferred embodiment of the invention, support links28are manifested as rotatable rollers so that product24and sleeve22can be rotated in a downstream heat tunnel to uniformly shrink sleeve22to snugly enwrap and conform to the contours of product24. In other embodiments not incorporating a sleeve-shrinking station, support links28may be fixed rather than rotatable. Whereas forming tube18of the preferred embodiment is moved vertically from a first position that is high to a second position that is low, it is understood that different transitional directions, for example from left to right, would be modifications within the scope of the present invention.

Vertical sleeve handling often involves a tubular machine component into which the cut sleeve is placed prior to discharging onto the product being labeled. A drawback of vertical sleeve handling is that the cut sleeve will fall through the tube unless the tube is matched closely enough to the size of the sleeve to be held in place by friction, or a holding device, e.g. a suction port, is provided. Since the extruded tubular sleeve will vary somewhat from one lot to the next, the vertical holding tube needs to be changed to accommodate the desired tight fit.

The present invention, as will be described below, provides a sleeve applicator that maintains the product and the tubular sleeve in horizontal orientation. Horizontal orientation allows a variation of sleeve diameter without generally requiring a change of sleeve holding tube. A known horizontal sleeve applicator is manufactured by Marburg Industries, Inc. of Vista, Calif.

SUMMARY OF THE INVENTION

The horizontal sleeve applicator described herein is configured to draw a length of flat tubing from a supply of tubular film and to open the flat tubing to a round configuration by use of an internal spreader and an external forming tube aligned with the supply. The opened sleeve is cut from the supply with a selected length positioned in the forming tube. The forming tube is next moved from its first position in alignment with the supply to a second position in alignment with a product to be enwrapped. The sleeve is next discharged from the forming tube onto the product. The sleeve is subsequently shrunk to snugly fit the product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The horizontal sleeve applicator10of the present invention, illustrated schematically inFIG. 1, is operative by moving a forming tube18between two horizontal, spaced apart, planes, noted α and β, respectively. Plane α indicates the horizontal level at which tubular film12is supplied into forming tube18of the invention apparatus, and plane β indicates the horizontal level at which the tubular film12, now cut to a selected length to form a sleeve22, is discharged from forming tube18and applied onto a product24. The traverse of sleeve22from plane α to plane β is effected by a reciprocating vertical movement of forming tube18from its first position18a(shown in dashed lines) to its second position18b, while sleeve22resides therewithin.

Tubular film12is drawn from a supply (not shown in this drawing) in the direction indicated by arrow A, i.e. downstream, to pass a cutter14, of any known type selected according to the shear characteristics of the tubular film12material. Tubular film12is an extruded plastic resin, for example polyvinyl chloride (PVC) or high density polyethylene (HDPE). In the preferred embodiment, a cutter14comprises a fixed blade and a movable blade. The movable blade is moved along a linear path that is perpendicular to planes α and β, and the fixed blade resides at a slight angle to the moving blade. A cutter of this type is described in detail in U.S. patent application Ser. No. 10/411,717, owned by the assignee of this application, and incorporated herein by reference. Other forms of cutter, for example a single blade cutter or a hot wire cutter, are considered within the scope of the present invention.

As tubular film12is moved forward in the direction of arrow A, a forward portion of tubular film12is inserted into forming tube18afor a selected length beyond cutter14. Cutter14then severs the selected length of tubular film12from the supply of tubular film, creating sleeve22. The selected length of sleeve22is typically chosen to substantially equal the length of product24to be enwrapped thereby. In other applications, the length of sleeve22is selected to be shorter than the length of product24so as to enwrap a portion, not the entire length, of product24. When sleeve22is severed from the supply of tubular film12, forming tube18ais moved downwardly to its second position at plane β with sleeve22residing therein, placing forming tube18bin axial alignment with product24. Product24is resting upon support links28of conveyor26. Product24is conveyed upon conveyor26in the direction indicated by arrow D. As shown, product24is relatively long and thin, for example a felt tip pen, and is best handled in horizontal orientation. Support links28are preferably formed with a tapered end29, residing closer to forming tube18bso as to reduce resistance to the assembly of sleeve22onto product24. It is to be understood that the stiffness and frictional characteristics of sleeve24affect the ease of assembly. When described below without regard to being at a level with either plane α or plane β in the apparatus, the forming tube will be designated as forming tube18. In the preferred embodiment of the invention, support links28are manifested as rotatable rollers so that product24and sleeve22can be rotated in a downstream heat tunnel to uniformly shrink sleeve22to snugly enwrap and conform to the contours of product24. In other embodiments not incorporating a sleeve-shrinking station, support links28may be fixed rather than rotatable. Whereas forming tube18of the preferred embodiment is moved vertically from a first position that is high to a second position that is low, it is understood that different transitional directions, for example from left to right, would be modifications within the scope of the present invention.

In the depiction of the present invention ofFIGS. 2 and 3, and also shown in the second position of forming tube18b(shown inFIG. 1), a mounting clamp20is provided to securely mount forming tube18b, while allowing rapid changing to another size forming tube18by releasing a clamp mechanism, as is known. Mounting clamp20is omitted from the depiction of the first position of forming tube18a, shown in dashed lines inFIG. 1for reasons of clarity. Mounting clamp20is affixed to a driver36so as to be moved in the direction indicated by arrows B, B′.

Referring further toFIG. 1, with forming tube18bin its second position in alignment with product24, upon detection of the proximity of product24by a sensor (not shown), a driver30thrusts a ram32forward in the direction indicated by arrow C to discharge sleeve22from forming tube18bonto product24. Driver30and ram32rapidly retract after discharging sleeve22from forming tube18b. A stop34is provided behind the rear end of product24in order to prevent product24from being moved backwards as sleeve22is assembled thereto. The diameter D of sleeve22is greater than the diameter d of product24by an amount sufficient to allow ease of assembly. In the preferred embodiment, conveyor26moves continuously and does not hesitate during the discharge of sleeve22onto product24, which is accomplished by a quick thrust-and-retract movement of driver30and ram32.

The processing of plastic resins through extrusion dies to form tubular film12typically results in a small variation of tubing diameter from one production run to another. In the case of known vertical assembly sleeve applicators, means are needed to ensure that the cut sleeve does not fall out of the vertical holder, whether a forming tube or another structure. This means for securing the cut sleeve can be accomplished by the holder bore being substantially equal to the diameter of the sleeve exterior to fit snugly together, thus requiring a change in holder size for virtually every production run of tubular material. Another known means to accommodate sleeve diameter variations in vertical applications is to provide a securement means, for example a suction nozzle as described in U.S. Pat. No. 4,914,893 to Strub, to attach temporarily to the sleeve side. As will be understood, an advantage of maintaining forming tube18of the present invention in horizontal orientation is that small variations in sleeve diameter are tolerated without the need to secure the sleeve from prematurely falling out of the holder.

Referring now toFIG. 2, a supply40of tubular film12is illustrated as being rotatably mounted at the right extremity of horizontal sleeve applicator10as tubular film12is drawn by drive rollers46in the direction indicated by arrow A. A tube spreader42is positioned within tubular film12upstream of drive rollers46. As tubular film12is moved over spreader42, tubular film12is spread to begin the opening process, which is completed within forming tube18. Drive rollers46pull tubular film12from supply40and over spreader42and then push the downstream length of tubular film12between idler rollers48, through cutter14and into forming tube18a. Idler rollers48are used as an alignment guide for tubular film12and can be replaced by another style of guide. The overall length of sleeve22may be less than or greater than the length of forming tube18b. Preferably, sleeve22is longer than forming tube18so that a short length of sleeve22extends out of the discharge end of forming tube18to reside as close as practical to product24(seeFIG. 1), optimizing assembly accuracy.

As described in general above, drive rollers46move tubular film12forward into forming tube18ain its first position, and cutter14severs the selected length off within forming tube18a. Forming tube18athen moves downwardly to its second position at18bwhere ram32, driven by driver30, discharges cut sleeve22onto product24(seeFIG. 1). As seen inFIG. 2, forming tube18ais moved in the direction indicated by arrow B by driver36to the second position of forming tube18b. Driver30and driver36are, for example, pneumatic cylinders as are generally available, or another type of linear actuator. In a variation of the present invention (not shown), a plurality of forming tubes18may be mounted on a rotatable plate such that in the first position, a first forming tube18receives a sleeve22while another sleeve22is discharged from a second forming tube18in the second position onto product24. The plate then is rotated to place the first forming tube18in position to receive a further sleeve22and the second forming tube18to discharge an inserted sleeve22onto a subsequent product24.

Referring now toFIG. 3, details of the supply of product24into horizontal sleeve applicator10are illustrated. The machine sections and actions that are described above in reference toFIGS. 1 and 2are incorporated generally in the right portion ofFIG. 3, including supply40, tubular film12and forming tube18b. In the left portion ofFIG. 3, an open-top hopper52is mounted to receive a quantity of product24in horizontal orientation, but not linearly dispersed. Hopper52includes rotating gate54for linearly dispersing individual ones of product24sequentially onto conveyor26, nested between adjacent support links28. Conveyor26is driven in the direction indicated by arrow D by a motor or other means (not shown) to position product24in alignment with forming tube18band sleeve22. Next, conveyor26continues to carry sleeve-enwrapped product24in the direction of arrow D to have sleeve22shrunk, by heat or other means, so as to snugly fit to product24.

Details of forming tube18are shown inFIGS. 4A and 4B, the latter view being a cross section view through the center of the former view.FIG. 4Ashows the entry end of forming tube18in elevation view. It should be understood that the outside shape of forming tube18is a design choice, and not considered of significance to the invention. Forming tube18has a bore60extending longitudinally therethrough. The diameter D′ of bore60is equal to or slightly greater than a maximum outside diameter D of sleeve22(seeFIG. 1), so that a maximum size sleeve22will fit slidingly within bore60, and a sleeve22with a smaller diameter will rest loosely therewithin. It is further understood that forming tube18has an internal channel with a cross sectional shape comparable to the cross sectional shape of the product to be enwrapped. In the case described herein, product24(FIG. 1) is round in cross section, whereas forming tube18has a circular bore; in a case where product24is of another cross sectional shape, e.g. square, the bore of forming tube18will be similarly shaped. A chamfer62is formed at the entry end of bore60to ensure that each entering sleeve22is moved into the center of bore60. A pair of guide grooves64are formed at approximately 180° displacement from one another. Guide grooves64, as shown clearly in cross section inFIG. 4B, are oriented at an angle φ to bore60. The selection of angle φ is largely empirical according to the characteristics of tubular film12and forming tube18. In the preferred embodiment of the invention, forming tube18is made of Delrin® plastic resin.

Whereas tubular film12, as shown inFIG. 2, is in rolled form on supply40, tubular film12, and subsequently cut sleeve22, will have residual creases at both edges thereof. By opening tubular film12over spreader42, the creases are forced open, but are not eliminated. The width W of the entry end of guide grooves64is sufficient to receive the residual edge creases of sleeve22. Preferably, width W is equal to the lay flat width of tubular film12, i.e. the distance between edge creases when the tubing is flat. Guide grooves64taper toward bore60to force sleeve22from its creased, substantially elliptical cross sectional shape to a substantially round shape in forming tube18to smoothly enwrap the round cross section of product24.

Referring now toFIG. 5in which the method steps for practicing the present invention are delineated, a supply40of flat tubular film12is provided in step1. In step2, the flat tubular film12is caused to be opened by passing over a spreader42. When forming tube18is in its upper position, flat tubular film12is driven by drive rollers46for a selected distance toward forming tube18in step3to insert a selected length of tubular film12into forming tube18ain step4. In step5, tubular film12is cut by cutter14at the selected length to form sleeve22. In step6, forming tube18is moved from its upper position to its lower position to be aligned with a height of a product24. Product24is positioned in axial alignment with forming tube18in step7, and sleeve22is discharged from forming tube18to enwrap product24in step8. In step9, forming tube18is returned to its upper position, and the process is reset to step3in step10to repeat the cycle.

While the description above discloses a preferred embodiment of the present invention, it is contemplated that numerous variations and modifications of the invention are possible and are considered to be within the scope of the claims that follow.