US3060888A

US3060888A - Envelope gumming machines

Info

Publication number: US3060888A
Application number: US70823A
Authority: US
Inventors: Nifontoff George; Jack M Ciccone
Original assignee: FL Smithe Machine Co Inc
Current assignee: FL Smithe Machine Co Inc
Priority date: 1960-11-21
Filing date: 1960-11-21
Publication date: 1962-10-30
Anticipated expiration: 1979-10-30

Description

Oct. 30, 1962 e. NlFONTOFF ETAL ENVELOPE GUMMING MACHINES 10 Sheets-Sheet 1 Filed Nov. 21, 1960 Ac/r M. d/ccoA s ATTORNEYS INVENTORS 1962 G. NIFONTOFF ETAL 3,060,888

ENVELOPE GUMMING MACHINES l0 Sheets-Sheet 2 Filed Nov. 21, 1960 mbwil 1962 G. NIFONTOFF EI'AL 3,060,838

ENVELOPE comma MACHINES 1O Sheets-Sheet 3 Filed Nov. 21, 1960 Ill nvil m 0 T N E V w W x 6 i W JM ATTORNEYS Oct. 30, 1962 G. NlFONTOFF ETAL 3,

ENVELOPE comma MACHINES l0 Sheets-Sheet 4 Filed Nov. 21, 1960 F 5 5mm M 5 a WWW w a. Fm wan h m W 5 M 3 M QN NN M\\\ x Jww w. WW Qm 1 a NY 30, 1962 G. NlFONTOFF ETAL ,06

ENVELOPE GUMMING MACHINES Filed Nov. 21, 1960 10 Sheets-Sheet 5 4 INVE ToRs FF EOQGE ImNTU Jo'c/r /)7. C/cc a/vs BY ATTORNEYS Oct. 30, 1962 G. NIFONTOFF ETAL 3,060,888

ENVELOPE GUMMING MACHINES Filed Nov. 21, 1960 10 Sheets-Sheet 6 aa 32 1Z8 6 INVENTORS 04 515 MFoA/mq Y JPCAM Caro/v5 ATTORNEYS 1962 G. NlFONTOFF ETAL 3,050,888

ENVELOPE GUMMING MACHINES Filed Nov. 21, 1960 10 Sheets-Sheet 7 INVENTORS 02 5 IFONTOFF BY 146K 07 mica/v5 W W 4 M ATTORNEYS 1962 G. NIFONTOFF ETAL 3,060,883

ENVELOPE GUMMING MACHINES l0 Sheets-Sheet 8 Filed Nov. 21, 1960 INVENTORS CCONE 9721144 MJM ATTORNEYS Oct. 30, 1962 G. NIFONTOFF ETAL 3,060,888

' ENVELOPE GUMMING MACHINES Filed Nov. 21, 1960 10 Sheets-Sheet l0 En ve/ope Mach/x1e. Drive IN VEN TORS Geo/e 5 /V/FON TflFF JACK deco/v5 BY ATTORNEYS tates hater-r;

3,060,888 Patented Oct. 30, 1962 @ilice 3,659,838 ENVELOPE GUMMING MAQEEJES George Nifontoii, Nyack, and Jack M. Ciccone, W estbury, N.Y., assignors to F. L. Smiths Machine (Iompany, Inc., New York, N.Y., a corporation of New York Filed Nov. 21, 196i), Ser. No. 70,823 14 Claims. (Cl. 118l) This invention relates in general to pressure sensitive adhesive application machines and in particular to improvements therein which provide an applicator mechanism which prevents solidification of the adhesive in the gum box, minimizes adhesive stringing, easy to clean and adjust, and which will apply a uniform thickness of adhesive to an irregularly shaped area applicator die.

It has been found that where latex gum or other typical pressure sensitive adhesives are to be applied to envelopes and the like, there is a tendency for the gum to coagulate along the operating parts of the applicator mechanism as it is being transferred from the latex reservoir to an applicator die via an intermediate adhesive pick-up drum. The latex gum has an increased tendency to coagulate whenever it is exposed in thin layers and wherever its flow is restricted, such as by scrapers. It has been found that small films or layers of the gum solidify very rapidly and any stagnant areas of the gum surface are similarly subject to rapid solidification. Once the latex gum has solidifiied on the applicator or mechanism in the latex gum reservoir, it is not possible to redissolve these particles in the reservoir liquid. Thus, in present day latex gum applicators, great difiiculty is encountered in maintaining the operating parts clean and the gum reservoir supply sufficiently liquid to permit continuous pick-up by a reservoir roller and transfer the adhesive therefrom to an applicator die.

In accordance with one modification of the present invention, there is provided a novel latex gum applicator mechanism and improved gum box construction which is adjustably positionable on the bed of a conventional envelope making machine. The novel mechanism employs an improved gum box construction which includes an adjustable scraper mechanism which is located in close proximity to a continuously rotating adhesive pick-up roller passing through the gum box. The contour of the scraper is capable of being adjusted to a bowed configuration so that the peripheral thickness of the adhesive upon the pick-up drum may be varied. The entire scraper mechanism is pivotally supported and rotationally biased so that solidified latex particles or foreign matter that may accumulate behind the scraper mechanism may be readily released therefrom.

Another aspect of the present invention is its unique design which substantially inhibits the coagulation or solidification of the latex within the reservoir, about the pick-up drum, and upon the applicator .die. Because pressure sensitive adhesives, such as liquid latex, are most susceptible to coagulation when in the form of a thin film, the invention employs a continuously rotating pickup drum carrying an adhesive layer of substantial thickness. The latex thickness is sufiiciently great to reduce any drying thereof to an inappreciable amount. The speed of the continuously rotating pick-up drum is also suificiently fast to accomplish rewett-ing of the latex layer in the reservoir prior to any drying effect. The rotation of the drum within the latex reservoir sufficiently agitates the liquid therein thereby also inhibiting any solidification of the surface of the latex within the reservoir. This portion of the invention is also enhanced by the location of the scraper plate just above the latex level in the reservoir, in close proximity with the drawing surface of the pick-up drum. The latex removed from the drum in this manner is suificiently great to completely fill up the wedge-shaped gap between the scraper plate and the rotating drum to thereby avoid air contact of the excess gum being returned to the reservoir.

In order to transfer a uniform thickness of liquid latex from the pick-up drum to the rotating peripheral surface of an adjacent applicator die, a unique die configuration and mounting is employed. Because the transfer of the latex from the drum to the die is accomplished by a wiping like action between two members having difierential peripheral speeds, a novel die configuration is used wherein the leading edge of the applicator die employs an obtuse angle to prevent latex build up, while the trailing edge employs an acute angle to reduce latex carry over. The improved transfer of the liquid latex from the drum to the die is further enhanced by the eccentric mounting of the die upon its support shaft which provides a squeezing type closure between the die face and the thin film of latex on the pick-up drum.

A feature of the invention is that it may easily be positioned upon a conventional envelope making machine in such a manner that the rotary applicator die is driven by the envelope machine in timed relation with the envelopes thereon, while the pick-up drum is continuously rotated to inhibit the formation of a solidified layer thereon. In this manner, when the envelope making machine has been stopped for one reason or another, no clogging of the gum applicator will occur. The invention is suitably interlocked so that whenever the envelope machine is stopped, the latex drum rotational axis is shifted so that the drum may be continuously rotated without the accumulation of latex upon the stopped applicator die. Likewise, an electrical interlock is provided and suitably coupled to a mechanical camming device so that whenever an envelope is missing from the feed of the envelope making machine, the applicator die rotational axis is repositioned to prevent the application of latex to the exposed envelope delivery drum. In this manner it can be seen how the invention, under the circumstances of either a missing envelope, or during a temporary machine shut down, will not become inoperative due to glue solidification nor will there be an unwanted application of latex to the envelope delivery drum, or to the stopped applicator die.

Another feature of the invention allows the clearance adjustment of the applicator die to the envelope delivery drum without affecting the adjusted clearance between the applicator die and the adhesive pick-up roller, and vice-versa. The lack of interplay between these two critical adjustments facilitates the adjustment of each and reduces machine set-up time. This feature is provided by the novel arrangement of par-ts'wherein the pick-up roller and the applicator die are mounted on a slidable carriage assembly which is in turn located upon the bed of the envelope machine. The entire carriage assembly is adjustable relative to the machine bed while the adhesive pick-up roller is adjustable on the carriage relative to the applicator die rotational axis.

In another form of the invention wherein the envelope travels in the direction parallel to the applied gum strip, optimized gumming is accomplished by employing a wiping, or differential linear speed rate between the envelope blank and the strip applicator die. In this form of the invention, a unique transverse positioning cam arrangement may be employed to permit the forming of gum strips which bend and complement the envelope flap shape.

Accordingly, it is an object of the invention to provide a pressure sensitive adhesive applicator mechanism including means for maintaining a uniform thickness of adhesive on the applicator die regardless of its contour of shape.

A further object of the invention is to provide a latex gum applicator mechanism including novel adjustable scraper means arranged in the latex gum box directly on top of the level of the liquid and including means for controlling the film picked up by pick-up roller and for returning excess latex to the reservoir without exposing it to A still further object of the invention is to provide a gum applicator mechanism including adjustment means which compensates for the latex demands of an irregularly shaped multi-element rotating applicator die.

Yet another object of the invention is to provide a novel mechanism for applying substantially parallel adhesive panels of uniform thickness latex.

Another object of the invention is to provide a gum applicator which has .a pivoted scraper bar.

A still further object of the invention is to provide a machine wherein latex gum is evenly applied and transferred between adjacent rotating surfaces by employment of a wiping action rather than by a rolling action.

Yet another object of the invention is to provide a latex gum application machine wherein the applicator die roller is both rotated upon the envelope blanks and oscillated along its axis of rotation to provide the desired adhesive panel contour.

Other objects and advantages of the invention will become apparent and the invention will be fully understood from the following description and drawings in which:

FIG. 1 is a perspective view of the invention as adapted to an envelope making machine;

FIG. 2 is a perspective view of a typical envelope after the latex adhesive has been applied;

FIG. 3 is a side elevation view of the embodiment of FIG. 1 with portions broken away and portions in section;

FIG. 4 is a fragmentary top plan view of the invention;

FIG. 5 is a front View of the invention as attached to an envelope making machine;

FIG. 6 is a partial section showing the applicator die camming mechanism taken along line 6-6 on FIG. 4;

FIG. 7 is a partial sectional view of the latex reservoir and scraper plate taken along line 77 of 4;

ment of the invention wherein the latex drum applicator mechanism is located below the horizontal center line of the envelope machine delivery;

FIG. 18 is a sectional view taken along line 1818 of FIG. 17;

FIG. 19 is a perspective view showing another embodiment of the invention wherein the envelope travels in a path parallel to the applied strip of adhesive;

FIG. is a side elevation view of FIG. 19;

FIG. 21 is a partial section taken along line 2121 of I FIG. 20 showing the axial movement mechanism of the FIG. 8 is an enlarged view of a portion of FIG. 7 showing the operation of the scraper plate;

FIG. 9 is a perspective view of a modified form of applicator die shape;

FIG. 10 is a partial view of an envelope containing gummed areas as applied by the applicator die shape of FIG. 9;

FIG. 11 shows an envelope having tapered adhesive areas;

FIG. 12 is a broken view of the required scraper blade adjustment relative to the adhesive drum in order to obtain a uniform adhesive thickness throughout the width of the tapered adhesive panels shown in FIG.

FIG. 13 is a schematic representation of the relationship between the applicator die and the adhesive pick-up roller when. the applicator die surface is concentric to its center of rotation;

FIG. 13a is an enlarged diagrammatic view showing the amount of adhesive removed from the pick-up drum with a concentrically mounted applicator die;

FIG. '14 is a diagrammatic representation of the improved eccentric applicator die mounting of the invention;

FIG. 15 is an enlarged diagrammatic view of the wiping action of the applicator die against the adhesively coated pick-up drum for applying adhesive along line 1=515 in the envelope of FIG. 11;

FIG. 16 is an enlarged diagrammatic view of the wiping action of the applicator die against the adhesively coated pick-up drum taken along line 161'6 of FIG. 11;

'FIG. 17 is a side. elevation view of another embodienvelope gumming rollers;

FIG. 22 is an electrical schematic showing the various electrical interconnections between the machine elements.

Referring to the drawings, the invention as embodied in FIGS. 1 through 16 includes an envelope making machine delivery portion generally designated A, a swingable rotating applicator die portion B, and a continuously rotating adhesive pick-up drum and gum box portion C.

Although the invention as described is shown in combination with an envelope making machine, it should be realized that the invention is equally useful in the application of a gum like latex adhesive to any number of varied paper products, not necessarily envelopes.

The envelope machine portion A includes a delivery drum 10 and a series of spaced envelopes 12 passing thereover. The envelopes 12' are suitably secured to the periphery of the drum by means (not shown) and are carried about the periphery of the drum and released therefrom on a lower portion thereof also by means (not shown). The drum Ill is mounted upon a rotatable shaft 34 which is driven by a chain 16 through a sprocket member 18 attached to one end of the shaft 14-. The entire delivery drum assembly is mounted upon spaced upstanding envelope machine bed side plates 2020 which contain a pair of inverted T keyways 22. Fastened to the shaft 14 at one end of the drum 10 is a drive gear 24 which provides the drive for the applicator die portion B of the invention.

The adhesive applicator die portion generally designated 13 and the adhesive pick-up drum and gum reservoir portion generally designated C, are mounted upon a carriage member 26 which is slidably positionable upon the machine bed side plates 2l20 and engages with the keyways 22 therein.

The rotating applicator die portion B of the invention is pivotally supported upon trunnion screws 28 engaged into depending portions of the carriage member 26 and includes a generally cylindrical applicator die portion 30 mounted upon a horizontally disposed shaft 32. The shaft 32 is supported at each end by a pair of upstanding swingable side support members 34 which are pivoted at their lower end on the aforementioned trunnions 28. Located upon the shaft 32 in engagement with the envelope drum gear 24 is a gear 36. At the opposite end of the applicator die shaft 32 is a shaft rocking assembly generally designated 38. The shaft rocking. mechanism 33 includes a solenoid 40 having a reciprocable plunger member 42 and a roller cam follower 44 located thereon. The plunger 42 is held in either extended or retracted position with the aid of a spring biased detent ball 45 engaging notches 47. The solenoid 40 is supported above the envelope machine bed and attached to carriage member 26 by a support member 46. Operating in conjunction with the shaft rocking solenoid 40 is a cam member 48 and a plunger return wedge 50 secured'on one end of the applicator shaft 32' in registry with the solenoid roller follower 44. An electrical control switch 52 which is connected via cycle switch circuitry (not shown) to the solenoid 49. The solenoid 4G is energized by the closure of the switch 52 whenever an envelope is missing from the machine feed extending the follower 44 into vertical alignment with the cam 48. As the shaft 32 rotates, the entire applicator assembly B will be rocked clockwise about pivot screws 28 to prevent application of adhesive to the l Taxi:

exposed portion of the drum 10. As the shaft continues to rotate, the wedge 51 will contact the end of the plunger 42 to return it to its unextended position (FIGS. 1, 4 and 6). If a second envelope is also missing from the machine delivery drum, this cycle of solenoid energization, shaft rocking and wedge activated plunger return will be repeated. The spaced side supports 34 are resiliently biased toward the envelope delivery drum by a spring 54 having one end aflixed to the side plates 29 and the other end affixed to a portion of the side support 34. Extending from the support 34 is a stop pin member 56 which contacts a depending seat portion 58 of the carriage to limit travel of the applicator die mechanism in the direction of the envelope delivery drum. The right and left hand portions of the carriage 26 carry a pair of depending rear portions 60 having threaded carriage adjustment screws 62' located therein which, when operated, translate the carriage assembly 26 in a horizontal plane to vary the positioning of the center line of the shaft 32 with respect to the center line of the envelope delivery drum shaft 14. In this way, by the adjustment of screws 62 which are threaded into the machine bed 20, it can be easily seen how the carriage 26 and the applicator die may be adjusted relative to the delivery drum 111 to thereby vary the clearance distance between their operating surfaces. Because the required adjustments will be minor in nature, as changes in desired gne thickness or envelope thickness occur, movement of the carriage is possible while maintaining driving relation between the

gears

24 and 36.

The adhesive pick-up drum and gum box portion C includes a mounting plate 64 which is pivotally supported upon the carriage member 26 by a shoulder screw 66. The rearward portion of the plate 64 carries an extending member which has mounted thereon an adhesive drum drive motor 63, while the other end of the mounting plate 64 extends across the width of the machine bed member 20 and is releasably locked to the carriage plate 26 between a stop pin 69 and a plunger 70 carried by a solenoid 136. A tension spring 76 is secured to

upstanding pin members

72 and 74 mounted respectively on the mounting plate 64 and carriage 26. The spring 76 acts to continually urge the mounting plate 64 against the upstanding solenoid plunger 70. Mounted upon the horizontally swingable plate 64 is a gum box assembly designated generally 78. This assembly includes a substantially U-shaped frame portion 86 having upstanding side portions 82. Pivotally mounted between the sides 82 is a continuously running adhesive pick-up drum 84 mounted upon a shaft 86 having at one end a pulley member 88 connected by a belt 90 to the motor 68. The speed of shaft 86 may be adjusted by varying the axial position of one-half of the pulley 88 to thereby change its effective diameter. Any suitable belt tension adjustment means may be employed such as elongated mounting slots 89 in the motor base to obtain proper tension for any desired speed setting of the pulley 88. Supported within the U-shaped frame member 80 beneath the rotating pick-up drum 84 is a substantially rectangular adhesive reservoir 92 which is suspended between the side plates 82 by projecting pins 94 which engage a plurality of notches 96 in the side plates, so that the adhesive reservoir is easily removable from the frame 80 to allow for frequent cleaning. Pivotally supported between the side members 82 on a shaft 98 is an adhesive scraper assembly generally designated 100. The scraper assembly includes side members 102 which depend from the shaft 98 into the adhesive 112 contained in the reservoir 92 therebelow. Secured to the lower portion of the side members 102 is a horizontally elongated scraper plate member 104 which extends for the width of the pick-up drum 84 to effectuate the application of a controlled thickness of adhesive to the drum. The scraper assembly support shaft 98 has an end portion projecting beyond the side plate 82 which has secured thereon a horizontally disposed shaft 106. Contacting one end of the shaft 106 is an adjustment screw 108 while the opposite end of the shaft is resiliently biased in a downward direction toward the mounting plate 64 by a spring 111). The spring 110, operating through the shaft 106 against the adjustment mechanism 108, acts to continuously urge the shaft 98 and the scraper assembly mechanism attached thereto in a clockwise direction so that the edge of the scraper plate 104 is held in close proximity to the periphery of the drum 84 as determined by the setting of screw 108 (see FIGS. 1 and 7). Midway along the length of the shaft 98 is a plate adjustment screw 114 which is threadably engaged to the shaft 98 and projects to contact the mid-portion of the scraper plate 164 to warp or deform its edge portion adjacent the drum 84 periphery so that the spacing therebetween is varied along its length. Referring to FIG. 12, downward turning of the adjustment screw 114 causes the bending of the scraper plate 104 to create a gap of increased thickness in the center portion of the blade. This adjustment is found desirable for the application of a. non-uniform thickness coating to the pick-up drum periphery when irregularly shaped applicator die contours are employed such as a die (not shown) shaped in ac cordance with the adhesive panel outline 116 of FIG. 11 for reasons to be described later.

The arrangement of the adhesive reservoir 92 in one form employs an inverted latex supply bottle 119 which operates in well known fashion to maintain the latex 112 at a uniform level within the reservoir. The reservoir is positioned under the continuously rotating pick-up drum 84 so that the bottom portion of the drum passes through the latex in a counterclockwise direction (see FIGS. 7 and 8). Because of the drum rotation and the substantial viscosity of the adhesive, a wedge shaped buildup of adhesive forms between the edge of the scraper blade 104 and the drum. That portion of latex not required upon the drum is wiped or squeezed back down into the reservoir without exposure to the air in the portion beneath the scraper blade edge, thereby inhibiting any tendency of the solidification of the latex in this area. The remaining exposed area of the latex 112 in the reservoir 92 is maintained sufficiently agitated to inhibit any tendency of surface coagulation thereon.

The entire gum box assembly 78 is adjustably posi tionable upon its mounting plate 62. The positioning mechanism includes a pair of threaded adjustment screws 118 which pass through overhanging edge portions of the frame member to contact the edge of the mounting plate 64. After a suitable lateral position adjustment is made of the gum box assembly 78 upon the mounting plate 64, it may be locked thereto by the tightening of locking bolts 120 disposed thereunder which are threaded into the plate 80 through elongated apertures 122 in the mounting plate 64 (FIG. 3). This adjustment and locking arrangement permits the adhesive pick-up drum and gum box assembly to be positioned, as a unit, to the desired peripheral clearance between the drum 84 and the adjacent rotating applicator die

surfaces

124, 126 of member 30.

Referring to the novel applicator die portion of the invention (shown in FIGS. 14, and in greatly enlarged scale in FIGS. 15 and 16 wherein the surface of drum 84 is laid out in a plane for illustrative purposes), a shaped die portion 30 is secured to the shaft 32 by a journal cap 31 so that various shaped die portions may be readily interchanged. The die, in the embodiment shown, employs first and second die surfaces respectively numbered 124 and 126, each having a leading edge obtuse angle surface 128 which reduces any build-up, or scooping out effect, when brought into contact with the thin film of latex on the adjacent pick-up drum 84. The trailing edges of the

die portions

124 and 126 are provided with acute angle surfaces 129 to substantially reduce the tendency for any build-up upon the trailing portions of the die. The novel manner of transfer of adhesive from the rotating pick-up drum 84 to the differentially moving applicator die 30 is accomplished by the eccentric location of the surfaces 124, .126, relative to the center of rotation of the shaft 32. As these surfaces rotate into adjacent position with th oppositely rotating pick-up drum, a uniform transfer of adhesive is accomplished from the drum onto both of the die portions. Ordinarily, without the unique eccentric location employed in the invention, as shown in FIGS. 13 and 13a, a pure interfering wiping closure motion would result in a build-up of latex on the leading edge of the die face 124 and because the second die face 126 would be no closer to the drum '84 as it passed, a thinner application to the second die face 126 would result, due to the previous removal of latex from the drum by the first die surface 124. The invention, as will be readily appreciated from an analysis of FIGS. 14, 15 and 16, eliminates this latex starving and leading edge buildup by the provision of the eccentric mounting of the die upon its rotational axis. In operation, the closure of the die faces 124 and 126, with the opposite moving latex film 131}, is a combination of both a wiping action and a squeezing action. This may be appreciated by inspection of FIG. 15 wherein the proportions have been greatly enlarged to illustrate the principle involved. The gap 132 between the trailing edge of the first die face 124 is shown as establishing a reduced thickness of latex upon the roller 84 due to the transfer of some of the latex onto the moving applicator die face 124. In order to transfer a like thickness of latex to the second die face 126 after the removal of some of the latex by the first die 124, it is necessary to position the die 126 further to the right in the drawing. This is effected by the eccentric location of the die surfaces relative to the shaft 32 center of rotation. Because of the combined squeezing and wiping action of the die face relative to the latex film 130, no die leading edge interference with the adhesive is required in order to transfer a suificient amount of latex onto the die faces 124, 126 as would be required in FIG. 13a, not incorporating eccentric die mounting. Referring to FIG. 16, it will be observed that the thickness of the film 130 above die 124 is larger than the corresponding thickness of FIG. 15. This varying thickness of the latex layer 130 upon the drum 84 has been effected by the bowing of the scraper blade 104 in its center portion by the set screw 114 as previously described. This arrangement of non-uniform latex thickness upon the applicator drum is particularly desirable in applying the gum panels 116 of FIG. 11 wherein the end portions are thinner than the central portions of the panel. Because the area and amount of adhesive needed is larger in the center of the envelope, the invention provides an increased latex thickness in this portion of the drum. At the ends of the drum, the removed amount oflatex being less, it is desirable to provide less thickness of latex on these portions. Because the invention varies the amount of cement along the length of the applicator drum, it compensates for the varying area of the end portions of the gum panels .116, and thereby maintains -a uniform thickness of gum transferred to the applicator die

surfaces

124 and 126 throughout their widths. Obviously, an equivalent compensation technique could be employed wherein in lieu of varying the gum layer thickness, the die surface could be shaped by appropriate machining, to provide a non-uniform clearance with the latex 130 which would effect a similar compensation for maintaining uniform adhesive thickness over the entire breadth of the dies 124 and 1126.

In operation, as the envelope delivery drum is rotated in a clockwise direction, a pair of substantially parallel adhesive panels are applied by the die faces 124 and 126. Upon each revolution of the shaft 32, the die surfaces are rewetted with liquid latex from the rotating drum 84 by the combined squeezing and wiping actions previously described. It should be noted that the applicator die 30 is rotating in a counterclockwise direction along with the adhesive roller 84, which results in a differential movement between their adjacent surfaces. Obviously, although the respective shafts have been shown as rotating in the same direction to accomplish a differential movement therebetween, they could be rotated in opposite directions at different peripheral speeds to accomplish the same wiping transfer action of latex from the periphery of the drum 84 to the die faces. When, as frequently happens, an envelope is missing from the delivery of the fabrication machine A, a sensing microswitch device 52 will signal the absence thereof and effect the energization of solenoid 40. When solenoid 40 is energized, the plunger '42 carrying the cam follower 44 will be transferred into alignment with the cam 48. Because the solenoid 40 is rigid with respect to the carriage 26 While the applicator die supports 34 are free to rock, the camming action of follower 44 on the cam 48 will result in the translation of the entire applicator die shaft assembly to the right (see FIGS. 1 and 6), thereby preventing the application of adhesive to that portion of drum '10 that would normally carry the missing envelope. Before a second revolution of shaft 32 occurs it is returned to its leftmost position by the bias spring 54 and will be correctly repositioned for a reapplication of latex to the die faces. This latter repositioning of the shaft 32 is effected by the rotation of wedge member 50 which contacts the end portion of the solenoid plunger 42, to return it to its original position. Obviously, if a second envelope is also missing, the solenoid 40 will be reenergized and a second rocking of the applicator die portion B will occur for each half revolution of shaft 32.

When the envelope making machine A is stopped, the solenoid 136 will operate to lower the plunger 70 thereby removing the stop locating the pivotal position of the mounting plate 64. In this manner, whenever the envelope machine is stopped, plunger 70 retracts, plate 64 swings in a counterclockwise direction and carries with it the entire gum box and drive assembly 78 to effect a large clearance distance between the rotating pick-up drum 84 and the stationary applicator die 30, the latter of which has stopped with the envelope making machine. In this condition, because drum 84 continues to rotate, coagulation of the latex in the gum box is prevented during shutdown periods of the envelope making machine because the entire reservoir remains agitated and the continual rewetting of the drum within the latex supply will prevent any solidification. During the operation of the invention, if some solidified particles of latex do accrue in the reservoir, the design of the scraper bar is such that it may be moved away from the gum pick-up roller. This is accomplished by the pivotally supported construction of the scraper assembly which can be rotated in a counterclockwise direction about shaft 98 whenever any obstruction lodges under the edge of the scraper 104 (FIG. 7).

Referring to FIG. 22, a generalized schematic is shown in accordance with the invention, wherein a suitable source of electrical current may be connected to a pair of input terminals 200 to operate the envelope machine drive motor and the adhesive drum drive motor 68 in the following manner. Upon transfer of the main switch 300 the winding of solenoid 1-36 is de-energized allowing its associated plunger 70 to return to the uppermost position shown in FIG. 1, and at the same time the circuit through the envelope machine drive motor is completed. The adhesive drum drive motor 68 is controlled as desired through a conventional On-Olf switch designated 302. Connected in parallel with the envelope machine drive motor is the missing envelope circuit controlled by the feeler switch 52 in series with the rocking solenoid winding 40, so that application of adhesive to the periphery of the drum 10 is prevented when envelope blanks are missing therefrom as previously described. A control means designated 306 is connected in series arrangement with the rocking solenoid 40 circuit so that the feeler switch 52 is only effective to complete the circuit through the solenoid 40 during those time intervals when an envelope blank should appear at the delivery of the machine. In other words, the control means 306, which may be of any conventional arrangement, is effective to prevent the energization of solenoid 40 by the closure of the switch 52 inbetween the regularly spaced envelopes 12 on the machine delivery.

Referring to FIGS. 17 and 18, a modified form of the invention similar to the previous embodiment is shown. It differs therefrom in that the gum box assembly shown generally as 78 is suspended below the support plate 64 to effect the transfer of latex from a similar pick-up drum 84 to a corresponding die portion of a rotating die cylinder 38 onto a similar envelope delivery drum 10. This embodiment of the invention differs from the previously described embodiment in that the relative positioning of the latex applying mechanism is below the horizontal center line of the envelope machine delivery drum as distinguished from the previous embodiment wherein the mechanism was located above the plate 64. It should be understood that in this embodiment similar parts are identified with similar numbers (FIG. 19).

In the form of the invention shown in FIGS. 19, 20 and 21 where similar parts carry like reference numerals, a continuously rotating adhesive pick-up drum 84, arranged in a latex reservoir 92, is in rolling peripheral contact with a pair of cylindrical applicator dies 138, 138. The dies 138' have an axis of rotation substantially parallel to the pick-up roller axis of rotation and also are in peripheral contact with an envelope making machine delivery drum similarly numbered in the drawing. The delivery drum 10, as in the previous embodiment, carries a plurality of spaced envelopes 140 which are oriented with their adhesive flap portions in line with the dies 138. The adhesive strip applicator dies 138 are mounted upon a transverse shaft 142 which is pivotally secured in upstanding end plates 143. Attached to each end plate 143 is a control solenoid 144 which is journaled to the end portions of the applicator die shaft 142 in such a manner that the rotational axis of the dies 138, 138 may be raised and lowered in timed relation to the presence of envelopes 140 on the periphery of the drum 19. The energization of the solenoid 144 is controlled by a switch (not shown) similar to switch 52 in FIG. 1 to raise the shaft 142 when an envelope is missing and thereby raise the die faces 138 away from the drum 10. (As seen by dot-and-dash lines in FIG. 20.) Operating in conjunction therewith is an oscillating mechanism which axially positions dies 138, 138 in timed relation to the delivery of envelopes on the drum to effectuate a zigzag or cheveron application of adhesive strip (see FIG. 21). This mechanism includes substantially L-shaped

arms

146, 146 having pairs of cam follower pins 148 at each end thereof. The arms '146 are resiliently urged toward one another by a bias spring 150 attached between the opposing cam follower pins 148, 148. The other ends of the cam follower pins are engaged in an annular slot 152 formed in the collar portion of each of the strip applicator dies 138. The opposite ends of the arms 146 also carry a pair of opposed pins 149 and are operatively engaged with a pair of

complementary face cams

154, 154 secured to the drum support shaft 14. A dove-tail shaped guide portion 156 supports an intermediate portion of the arms 146 to provide a sliding bearing therefor. A pair of sprockets 158 and 169 are arranged at ends of the

shaft

14 and 142 respectively, and are connected by a drive chain 162 passing over an idler mechanism 164. The idler 164 is pivoted about a shaft 165 to permit raising of the shaft 142 within the elongated slots 167 in the plates 143. It can be seen by the arrows on the rotating members that all shafts rotate in the same clockwise direction thus resulting in a wiping motion and transfer of the glue between the periphery of the drum 84 onto the dies 13%, 138 and therefrom, also by a wiping motion, onto the envelope blank 140. With this arrangement of parts, optimized glue transfer is effected not only from the reservoir roller 84 to the applicator die 138, but also therefrom to the envelope. Those skilled in the art will readily appreciate how the intermittent raising and lowering of the die support shaft 142 in combination with the oscillating movement of the applicator die halves 138, 138 a horizontal plane results in the strip shaped application of the latex adhesive to the envelope coming from the machine.

Thus it can be seen how the various embodiments of the invention provide a novel latex gum handling machine which employs oppositely rotating or differential linear speeds to effectuate optimized gum transfer, employs eccentric applicator die motion to effectuate both a wiping and a squeezing contact with the adhesive on the picl -up drum, has an improved leading edge applicator die contour to prevent unwanted gum build-up, and employs a novel gum box and scraper blade assembly.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A liquid pressure sensitive adhesive applying attachment for a paper product machine having a bed and a drive means, comprising a carriage, said carriage including an adhesive reservoir, a drum arranged to rotate within said adhesive reservoir, means to rotate said drum, means for applying a thin film of adhesive to said drum, an applicator die mounted on a rotatable shaft in supports, said supports being pivotable from said carriage, said die axis of rotation being substantially parallel to said drum means axis of rotation, said die being in substantial peripheral contact with the surface of said drum, and coupling means between said applicator die shaft and the paper product machine drive means whereby when the paper product machine is operating adhesive will be transferred from the drum, to the applicator die, and then from the applicator die to the succession of paper products being fabricated by the machine.

2. Apparatus according to claim 1 wherein said carriage further includes means to adjust the lateral position of said carriage upon the machine bed to vary the distance between the applicator die and the succession of paper products within the machine.

3. Apparatus according to claim 2 wherein said carriage further includes means to adjust the peripheral clearance distance between the applicator die and the drum.

4. Apparatus according to claim 3 wherein said adhesive reservoir and drum means are mounted upon a support plate and are movable in a horizontal plane upon said carriage and includes stop means movable between an operative and an inoperative position to hold said support plate in predetermined position upon said carriage, control means for making said stop means inoperative when said paper product machine is inoperative, and bias means urging said drum means away from said applicator die toward said stop means.

5. An adhesive applying attachment in accordance with claim 1, wherein the adhesive reservoir is suspended from the carriage and the rotational axis of said drum and said applicator die is below the horizontal center line of the paper product machine.

6. An adhesive applying attachment according to claim 1, including means to reciprocate the applicator die axially along its rotational axis.

7. An adhesive applying attachment according to claim 6, wherein the coupling means includes a chain and idler sprocket.

8. A device for applying a liquid pressure sensitive adhesive to a succession of paper products being fabricated by a machine having a bed and drive means comprising, a carriage slidably positioned upon the machine bed,

said carriage including an adhesive reservoir, drum means arranged to rotate within said adhesive reservoir, means to rotate said drum, means for applying a thin film of adhesive to said drum, an applicator die mounted on a rotatable shaft in supports, said supports being pivotable from said carriage, said die axis of rotation being substantially parallel to said drum means axis of rotation, said die being in substantial peripheral contact with the surface of said drum means, and coupling means between said applicator die shaft and the machine drive means whereby when the machine is operating adhesive will be transferred from the drum means to the applicator die and then to the succession of paper products being fabricated.

9. Apparatus according to claim 8 wherein said applicator die has a cylindrical outer surface and said surface is eccentric to the axis of rotation of said applicator die.

10. Apparatus according to claim 8 including in addition actuating means for pivoting said applicator die shaft away from the succession of paper products and control means for operating said actuating means in response to an omission of a paper product from the succession of paper products in the machine.

11. Apparatus according to claim 10 wherein said applicator die and said drum means rotate in the same direction.

12. A latex tgum box comprising a reservoir of latex filled to a predetermined level, liquid latex supply means arranged to maintain a constant latex liquid level, a pickup drum arranged to rotate with a portion dipping into said liquid latex, a scraper assembly supporting bar extending across said reservoir with its axis substantially parallel to the axis of said pick-up drum, and a scraper assembly positioned on said scraper support bar and including a scraper plate portion arranged with its lower surface substantially level with the liquid latex level and in closely spaced relationship to said pick-up drum whereby liquid latex is scraped from the surface of said drum as it rotates and is returned directly to said reservoir without contact with air and means to deform the scraper plate portion to create a non-uniform clearance distance between the scraper plate portion and the pick-up drum so that a non-uniform thickness film of liquid latex is maintained on said pick-up drum.

13. A latex gum box according to claim 12 wherein said scraper assembly is adjustable toward and away from the surface of said pick-up drum.

14. A liquid latex gum box according to claim 12 wherein said scraper assembly is biased to urge said scraper plate portion in a direction toward contact with said pick-up drum.

References Cited in the file of this patent UNITED STATES PATENTS