US 3511138 A
Abstract available in
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Description (OCR text may contain errors)
May 12, 1970 'r. R. BAKER 3,511,138
BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES Filed April 20, 1967 '7 Sheets-Sheet 1 I NVENT 0R.
Thomas R. Baker 4.; ATTORNEY May 12, 1970 T. R. BAKER 3,511,138
BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES Filed April 20, 1967 7 Sheets-Sheet 2 INVENTOR. Tho/has A. Baker 1 A TTO/P/VEY May 12, 1970 T. R. BAKER 3,511,133
BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES '7 Sheets-Sheet 5 Filed April 20, 1967 SEE! BEIGE DUDE] CHIHIIU INVENTOR. Thomas R. Baker ATTORNEY May 12, 1970 -T. R. BAKER 3,511,133
BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES Filed April 20, 1967 7 Sheets-Sheet 4 I NVENTOR. Thomas 1?. Baker a). A TTORNEY 'r. R. BAKER 3,511,138
May 12, 1970 BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES 7 Sheets-Sheet 5 Filed April 20, 1967 EDGE SUEZ] DEED [BLISS DUDE DUDE] mama BED INVENTOR. Thomas R Baker 4;, A TTOR/VEY May 12 1970 T. R. BA KER BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF Filed April 20, 1967 STRINGING OUT OF ADHESIVES '7 Sheets-Sheet 6 INVENTOR. 7720mm 1?. Baker BY (f-014M W aw. A TTOR/VEY Fig. 6
May 12, 1970 'r. R. BAKER BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF" STRINGING OUT OF ADHESIVES '7 Sheets-Sheet 7 Filed April 20, 1967 59% 55 Pa .5 s i i 5 Ii INVENTOR. Thomas R. Baker I ATTORME)" United States Patent O BOX ERECTING DEVICES FOR REDUCING THE EFFECT OF STRINGING OUT OF ADHESIVES Thomas R. Baker, Los Altos, Califi, assignor to Kliklok Corporation, New York, N.Y., a corporation of Delaware Filed Apr. 20, 1967, Ser. No. 632,291 Int. Cl. B31b 1/44 U.S. Cl. 93-51 2 Claims ABSTRACT OF THE DISCLOSURE In an adhesive applicator of the type in which a nozzle deposits a bead or line of adhesive on paperboard and the like, uncontrolled deposition of a thread of adhesive strung out from the nozzle is avoided by depositing such strung-out adhesive on the previously deposited bead or line of adhesive.
BACKGROUND OF THE INVENTION Field of the invention Liquid adhesive discharged in the form of a bead or line from a nozzle or orifice tends to string out in the form of a thin thread after the flow of adhesive ceases.
This phenomenon is referred to as stringing-out in the paper box industry and is objectionable as it is unsightly and may produce an adhesive bond between areas of a folding box where no bond is desired.
Description of the prior art In the use of roller type adhesive applicators it is known to counteract the effect of string-out by the use of a further roller so placed as to catch and wind up the adhesive thread or string before it falls on the board.
However, where nozzles are used for depositing, by extrusion rather than spraying, a line or bead of adhesive wind-up rollers cannot be installed for various reasons, one of the principal reasons being lack of space.
Stringing out of adhesive can be reduced to some extent by nozzles comprising a built in shutoff valve so placed as to leave only an extremely small volume of adhesive available downstream of the shutofi point for stringing out. But as this volume cannot be reduced to zero, a string-out problem continues to exist.
SUMMARY OF THE INVENTION The present invention proceeds from the principle of rendering harmless the string-out which cannot be prevented by depositing the strung-out thread on the previously deposited adhesive line or bead.
This is particularly desirable and advantageous where the line or bead of deposited adhesive must be short and be localized to produce accurately defined glue spots.
The objects, features and advantages of this invention will appear more fully from the detailed description which followsaccompanied by drawings showing, for the purpose of illustration, a preferred embodiment of the invention. The invention also resides in certain new and original features of construction and combination of elements, as well as steps and sequences of steps hereinatfer set forth and claimed.
Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages and a manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying drawings.
3,511,138 Patented May 12, 1970 FIG. 1 is a perspective View of the adhesive applying and box forming portion of a box forming machine illustrating the instant of delivery of a flat box blank;
FIGS. 2 to 5 are sequential views illustrating the operation of the adhesive applying mechanism of the machine;
FIG. 6 is a perspective view of a portion of the mechanism for moving the applicator nozzles;
FIG. 7 is a perspective view of the adhesive supply reservoir and adhesive feeding mechanism; and
FIG. 8 is a sectional view of a typical construction of an adhesive applying nozzle used in the device.
In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.
The drawings accompanying, and forming part of, this specification disclose certain specific details of construction for the purpose of explanation of broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the principles of the invention and that the invention may be incorporated in other structural forms than shown.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a blank feeding mechanism 11 of known construction comprising suction cups 12 is seen carrying a flat box blank B for deposit above a box forming die 13.
The die aperture is bounded by four angularly bent plates, of which plates 14 and 15 are designed to fold the box front and rear panel into upright position. Plates 16 and 17 serve to fold the box end wall panels into upright position.
The end panel folding plates 16 and 17 comprise horizontal portions 18 and 19 on which the end wall panels come to rest when the blank B is deposited by the feeder cups 12 (see FIGS. 2 and 3).
The die assembly further comprises corner flap folding elements 20, one at each die corner, for engaging and upwardly folding corner flaps 21 of the blank B. The folding elements 20 also comprise projecting edges 22 underneath which the edges of folded corner flaps snap, thus trapping the prefolded blank in position above the die aperture when the blank feeder withdraws (FIG. 3).
Details of the blank construction are best seen in FIG. 4. The blank comprises a bottom panel 23, front and rear wall panels 24, 25, respectively, end panels 26, 27, a cover panel 28 and a front flap 29 on the latter. The previously mentioned corner flaps 21 extend laterally from the front and rear box body panels 24 and 25, respectively, and it is one purpose of the box assembly procedure adhesively to secure the corner flaps 21 to the end wall panels 26, 27 by means of adhesive applied to the end wall panel within predetermined areas.
Two adhesive applicators 30- and 31 are provided for this purpose, each comprising a manifold housing 32 from which several applicator nozzles 33 project downwardly towards a blank resting on the horizontal plate portions 18, '19. Molten adhesive is supplied to the manifolds 32 through heated flexible ducts 34 from a melting pct 35 at the rear of the machine (FIG. 7) via an appropriate periodically operated feed pump.
Returning to FIGS. 1-3, the adhesive applicators are mounted for reciprocating motion towards and away from the die aperture 13 in a plane substantially parallel to the horizontal plate portions 18, 19.
For this purpose the applicators are mounted on mounting plates 36, 37, the far ends of which move in horizontal guideways, of which one is visible at 38 (FIG. 1). The near portions of the plates are secured to sleeves 39, 40 slidable on a rod which is barely visible at 41 behind the machine frame.
A bell crank lever 42 pivotally mounted at 43 engages the right sleeve 39 at 44. A bolt 45 extends downwardly from the sleeve 39 to a push rod 46 articulated to a doublearmed lever 47 at 48. The lever 47 is pivoted to the machine frame at 49, and a further push rod (not visible) extends from the other arm of the lever 47 to a similar pin on the sleeve 40 which for this reason moves in a direction opposite to the sleeve 39.
Helical springs '50, 51, best seen in FIG. 3, tend to urge the sleeves 39, 40 toward each other, thereby eliminating lost motion in the operating linkage, and further serve to maintain a cam follower 52 against a drive cam 53 shown in FIG. 6. The cam 53 is fastened on a drive shaft or driven shaft 54 of the machine. The follower roller 52 is mounted on one arm of a double armed oscillating lever '55 from the other arm of Which a push rod 56 extends to the second arm of the bell crank lever 42 projecting through an aperture 57 in the machine frame.
In order to facilitate the understanding of the adhesive applicator motion, a marker 58 was afiixed to the machine frame in a location flush with the end of the sleeve 39 in the position in which the applicators are fully retracted (FIG. 1). Immediately after deposition of the blank, the adhesive applicators 30, 31 begin to move towards each other (FIG. 2) and While so moving the adhesive feed pump is operated causing a stream of adhesive to be discharged from the nozzles 33 of the applicators.
Depending on whether the duration of discharge is brief or longer, a bead or a line of adhesive is being deposited at 59 on the end wall panels 26, 27 of the deposited blank.
In the position shown in FIG. 3, the applicators have approached each other to the maximum extent (compare the position of the end of the sleeve 39 with the marker 58) and the deposition of adhesive is completeexcept for the stringing out of the last portion of the discharged adhesive which is likely to form a tacky thread from the deposit bead or line 59 to the nozzle proper.
In FIG. 4 the applicators 30, 31 are shown to retract in order to clear the descending box forming plunger 60 which is about to drive the blank into the die throat (FIG.
As the applicators move away from each other the tacky string of adhesive falls on the previously applied adhesive bead or line.
The corner flaps are then folded inwardly of the end panels and an adhesive bond is formed between the corner flaps and the end walls by the applied adhesive.
Referring to FIG. 7, the adhesive feed pump 61 is mounted underneath the melting pot 35. A terminal fitting of the heated adhesive duct can be seen entering the pump housing at 62'. The pump 61 powered by a pneumatic servo-motor 62, the servo-motor being controlled by a solenoid-operated control valve. The control valve, in turn, is operated by a cam-controlled microswitch 63.
The control cam 64 is composed of two cam discs, each having a high portion and a low portion. By rotation of the discs relatively to each other the duration of actuation of the switch may be varied, and the discs are then fixed relatively to each other by clamping bolts 65. Suffice it to say that the switch 63 is actuated while its roller 66 engages the cam between markers 67.
A representative form of nozzle is shown in FIG. 8. It comprises a needle type valve element 68 which opens and closes a discharge aperture 69 in the nozzle housing 70. A helical spring 71 hearing against a flange '72 on the element 68 tends to maintain the valve element 68 in its closing position. Adhesive under pressure entering at 73 acts on the underside of the flange 72 and opens the valve when the pressure is suflicient to overcome the force of the spring which may be varied 'by means of a nut 74.
What is claimed is:
1. In a box erecting device comprising a die; transport means for depositing a flat folding box blank over the mouth of the die; a hot-melt adhesive applicator comprising a source of hot-melt adhesive, a discharge nozzle comprising a pressure-responsive valve means for opening the valve at a pressure above, and closing the valve at a pressure of the supplied adhesive below, a preset pressure limit, respectively, and a nozzle carrier for supporting said nozzle for reciprocating movement in a direction towards, and away from, the axis of the die, respectively, to extend during its forward stroke over a portion of a blank deposited on the mouth of the die and to withdraw from above said portion during the return stroke; a plunger movable into and out of the die for pressing said blank into the die and folding said blank portion toward a side surface of the plunger; and a pump operable in timed relationship with the plunger movement for periodically feeding molten adhesive under pressure to said nozzle, the improvement characterized by an actuating mechanism for said pump so timed as to cause adhesive under pressure to be fed to said nozzle exclusively during the forward stroke of said nozzle carrier,
, whereby filament of adhesive strung out after closure of said valve means and during the return stroke of said carrier is caused to settle on, and to be captured by, the liquid adhesive previously deposited by said nozzle during the forward stroke of the carrier.
2. The device defined in claim 1 in which said blank portion is a box wall panel, in which the nozzle carrier moves in a direction substantially normal to the surface of the plunger against which surface said panel is to be folded, and in which said pump is being actuated to deliver adhesive under pressure during only a fraction of the forward stroke of the carrier.
References Cited UNITED STATES PATENTS 6/1949 Curlee 118-25 2/1969 Wagner 118-411 X US. Cl. X.R.