US2928370A - Feeding device for adhesive in solid rod or rope form for coating applicators - Google Patents

Description

March 15, 1960 F. c. GROSS FEEDING DEVICE FOR ADHESIVE IN- SOLID ROD OR ROPE FORM FOR COATING APPLICATORS 2 Sheets-Sheet 1 Filed June 6, 1.957

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FEEDING DEVICE FOR ADHESIVE IN SOLID ROD OR ROPE FORM FOR COATING APPLICATORS Filed Jun e s, 1957 2 Sheets-Sheet 2 QM. &m 8 Q [H 1 kn m Wm R \muww a m W A H\ S w -1 3 M N\\\ l FEEDING DEVICE FOR ADHESIVE IN SOLID ROD R RGPE FORM FOR COATING APPLICATORS Frank Gross, Wilbraham, Mass., as'signor to Package Machinery Company, East Longmeadow, Mass, a cor-- poration of Massachusetts Application time 6, 1957, Serial Nb. 663,986

13 Claims. or. 118-600) This invention relates to improvements in devices for applying adhesive material to surfaces of the type in which the adhesive is supplied to the applying device in solid rod or rope form, and in which the adhesive is heated to bring it to a plastic or liquid condition, for

. application to the surface to be coated by an applying roll forming part of the applying device.

An applying device of the character to which the presentinvention is applicable is shown in copending application Serial No. 642,013, filed February 25, 1957.

More particularly the present invention relates to means for feeding the solid rod or rope of adhesive to the heating chamber and applying roll of the applying device.

In prior devices the adhesiverope has been fed into the applying portion of the device by driven feed rolls, or under constant continuous pressure exerted by springs or similar means.

Such prior feeding methods have proved unsatisfactory because of the variation in the pressure conditions created adjacent the applying roll when the adhesive has been brought to a liquid state, resulting in variations in the amount of adhesive advanced by the roll and an objectionable build of pressure during interruptions of the operation.

It is an object of the invention to provide a feeding" mechanism which is, to a substantial degree, automatically responsive to the adhesive needs of the applying roll and which is easily and finely adjustable to meet the requirements of differing operative conditions, various adhesive formulations and variations in temperature.

Other and further objects will be made apparent in the disclosures of the accompanying drawings and in the fol- Fig.5 is a sectional view substantially on line 5' of Fig. 2; V i

Fig. 6 is a detail view showing the under face of one of the feeder pawls; '1 Fig. 7 is a detail, generally perspective view of the roll engaging face of the supply plunger; and

Fig. 8 is a detail, generally perspective view of a lip member of the housing.

Referring to the drawings, the applying device is "shown as comprising a housing generally indicated at 1, made up of a member 2 which is channeled along one side as at 3 (Fig. .5), to form a.- guideway in which a supply: plunger 4 is mounted." The open side-of channel 3 is closed by a member 5 whichhis provided with suitable electrical heating units 6 and a thermostat 7.by which.

the heating units are controlled in a conventional and well tates Patent T 1 known manner. The members 2 and 5 are supported from a bracket 8, a block of heat insulating material 9 being interposed between the bracket and member 5. The members 2,5 and 9 are secured to each other and to bracket 7 by suitably positioned tap bolts 10.

An adhesive applying roll 15 is carried by a shaft 16 (as shown the roll is formed integral with the shaft) which is journaled as at 17 and 18 in the forward ends of members 2 and 5, the journal-bearings being lubricated through a suitable system of ducts as indicated at 19, Figs. land 5. The roll 15' is provided on its peripheral surface with a plurality'of adhesive receiving recesses 20, spaced from each other and from the edges of the roll. The adjacent end of plunger 4 is formed with an arcuate surface 21, having the same'radius as the surface of the roll, and is recessed to form a chamber 22, the arcuate surfaces of plunger 4 being dimensioned with respect to the dimensions and arrangement of the recesses 20 that the adhesive carried by the roll from chamber 22 is confined to that in the recesses 20. V The plunger 4 is formed with a bore 23 opening from cham ber 22 to the rear end of the plunger in which a tubular member 24 is threaded with a threaded portion of member 24 extending outwardly from the rear end of the plunger. A coupling member 25 formed of heat insulating material is threaded on .the rearwarclly extending portion of member 24 and turned into tight engagement with the adjacent end of the plunger 4. A tubular mem-; ber 26 is threaded into the rear end of coupling member 25 to tightly couple the members 24 and 26 together with a heat insulating washer 27 interposed between their adjacent ends. The open rear end of the channel 3 in memher 2 is bridged by a strip 29, of heat insulating material, secured to the rear end of member 2 by machine screws 30 and held spaced therefrom by sleeves 31 surrounding the screws. Coupling member 25 is formed with a flange 32 and a coiled spring 33' compressed between strip 29 and flange 32 resiliently urges the arcuate end of the plunger 4 against the peripheral surface of roll 15. The plunger 4 is held in proper radial alignment by guide screws 35 extending through member 2 into the channel 3.

Rearwardly of coupling member 25 the member 26 extends through a heating block 36 secured to the member 26 by screws 37. Block 3 6 carries an electric heating element 40 and a thermostat 41 by which theheating element is controlled in a conventional and Well known manner.

The adhesive is supplied to the device in a solid rod or rope form as indicated at A, and is fed into the rear end of tubular member 26 by means which are automatically responsive'to a change in back pressure on the rope. Rearwardly of the entrance to member 26 the rope A passesalong the bottom of grooves 45 and 46 formed respectively in successive, spaced blocks 47 and 48,

and beneath pawls 49 and 50 pivoted respectivelyin grooves 45 and 46,'which pawls are pressed into engagement with the rope A by respectiveleaf springs 52 which bridgethe grooves and are fixed to theblocks by screws 53.

The'springs engage screw 54, threaded in the pawls, by

which'thepressureexerted by the springs 52 on the rope A may be adjusted. The pawls arecohveniently provided with fingerpins 55 by which the pawls may be manually raised for initially passing the rope beneath the pawls. As

shown the rope engaging face of each pawl is recessedas' at 57 to provide forwardly directed sharp edges 58 engaging the sideportions of the rope, preventing rearward movement of the latter.

arm 63 fixed to one end of a ro'ckshaft 65 journaled in a bearing 66 extending from bracket 3. An arm 67, fixed I 5 of the high and low dwells maybe adjusted. .fl he cam roll 68 is urged against cam 69 by a spring 73 connected at one'end to bracket 8 as at 74, the other endbeing con nectedto the end of a threaded rod 75 extending through block 47 and provided with a knurled nut 76 by whiclrthe effectivetension of spring 73 may be adjusted. screw 77 holds'rod 75 in adjusted position in,block'47..

. Cam shaft 79 carries a sprocket 80 connected by a sprocket'chain 81 to a sprocket 82 on a constantly driven main drive shaft 83 powered from any suitable; source. Shaft 33 also carries a sprocket 8 4 connected by a sprocket chain 35 connected to a sprocket 86 on across shaft. 87. Shaft 87 carries a second sprocket 88 which is connected by a sprocket chain 89 to a sprocket 90 carried :by shaft 16 of applying roll 15. Thus the applying roll and cam 69 are constantly driven. A pivoted idler sprocket or roll 91 maintains desiredtension on the sprocket chain 89.

As block 47 is oscillated by cam 69 the rope or rod A of solid adhesive is engaged by pawl 49 on its forward stroke and advanced beneathpawl 50 and. into the tubular members 26, and 24, and into chamber 22. A screw 92 having a knurled head 93 is threaded through block -47 into engagement with stationary block 48 to adjustably limit the forward movement of block 47 and the length of the feeding strokeof pawl 49., A set screw 94 maintains screws 92 in adjusted position. As the, rope A advances through members 26 and 24 his softened and brought to a liquid state in chamber 22 bythe heat supplied, by

heaters 40 and 6 as later more fully described.

As previously described the formed end of plunger 4 makes an arcuate contact with the peripheral surface of roll 15 under the pressure of spring'33 so that the adhesive advanced from chamber 22 as the roll rotates, in the direction of the arrow in Big. 2, is confined to the recesses 20. The chamber 22 is provided with a transverse baffle 95, held in placeby a screw 96, .which is triangular :in cross section so that as the fluid adhesive is forcedinto the narrowing space between the face of. the roll '15 and the adjacent face of the baffie by the pressure on the adhesive in chamber 22 thepressure increases assuring a complete filling of the recesses 20. V

The walls of channel 3 opposite the peripheral surface of roll 15 are formed as arcuate surfaces on a radius a slightly greater than that of the roll so that the roll rotates as indicated at 97 with its peripheral surfaceclosely adjacent but free of contact with the housing formed by member 2 and block 5, the roll being heated byconduction from block 5 while the adhesive in the-recesses 20 is further radiantly heated from the closely adjacent housing walls as the roll surface passes outwardly of -the hous-' ing for application of the adhesive-in the. recesses to the surface of a box blank or other surface withwhich the portionvof the roll outwardly of the housing is brought into rolling contact. Preferably and as, shown, theroll makes contact with the surface to'wh'ich the adhesive is to be applied immediately after the adhesive filled recesses V 20 emerge from the housing and the adhesiveis transferred substantially cleanly to such surface. As best shown in Fig. 7, the lower'portion of the arcuate face of plunger 4' is relieved to form a channel 98 of decreasing width and depth from the outer'edge of the plunger to a line ad-' jacent the chamber.- 22 so that any adhesive retained at the edge of recesses 20, or'on the adjacent unrelieved portions of the surface of roll 15, will not be scraped or doctored off by the outer edge of the plunger but will be carried inwardly between the roll and the face of chanas a nel 9 8 and scraped or doctored back into the recesses 20 j by the inclined edges 99 and the transverse edge 100 at the inner end of the channel 98. The decreasing depth of the recesses 20 and prevents escape of adhesive from chamber 20 tothe channel .98.,

in case the formulation of the adhesive is such as to cause objectionable stringing. of the adhesive as the roll leaves the surface to which it is applied, a bar member 105,.having an arcuate surface 106 spaced from roll 15, is securedto the housing, as by screws 110. Any string formation is severed at the edge 107 and any portion of the strings drawn inwardly by the roll is melted by the heat conducted to bar and drains to the sides of the bar by outwardly extending channels 108 shown in Fig. 8.

By the structural arrangements above. described the feeding of the adhesive proceeds as follows. The adhesive in solid rope or rod form is forced into the tubular passage of member 36, which extends through the block 36 which is heated by the heater 40, under the pressure of spring '73 acting on pawl 49. The diameter or cross sectional dimensions; of the passage through member 26 with respect tothe diameter or cross sectional dimensions of the rope is made such that the rope makes a relativeheater-'40 under control of its thermostat 41.. The heat transferred to the rope in its passage throughmember 26 is insufficient to soften the rope to a point where substantial form stability is lost so the rope or rod acts piston fashion to maintain hydraulic pressure on the adhesive in the forward portion of passage 23 and chamber 22 which has been brought to a liquid state by heaters 6 under the control of thermostat 7.. The heat transfer to the adhesive-by heatersfi is made such that the adhesive in the chamber 22'is maintained at the best degree of viscosity for handling and application by roll 15 and under a predetermined pressure. As is apparent in Fig. 2 the passage in member 24.,tapers toward the chamber 22 so that as the adhesive becomes more fluid the rate of flow under the pressure being exerted by spring 73 through pawl 49 and the solid portion of the rope or rod A is balanced to the needs of roll 15. This balance of temperature, pressurejand flow conditions is nicely adjustable and automatically maintained for a given adhesive formulation by the adjustment of the i 7 spring pressure by means of screws 75, adjustment of the stroke of block 47 by screw 93, adjustment of the length of time that pressure is applied, by adjustment of the members-of cam 69, and the maintenance of the needed temperatures and temperature differential between members 36 and plunger 4 by the thermostats; By way of example a temperature of 210 F. at heater 40 and a temperature of 320 F. at the heaters 6 have been found a satisfactory for the thermoplastic adhesives presently sive rearwardly'between the incoming solid portion of the adhesive and member 26. If at any time, at the start of or during the feeding stroke of pawl 49, the back pressure equals the'pull of spring 73 the forward swing of block 57 will be inhibited and cam roll 68 will be held from contact with the low portion of the cam 69.

The adjustments provided, and above described, minimizethe tendency for back-pressure build up, but unavoidable, slight and temporary excesses of back pressure are automatically compensated for by the described inhibiting of the feeding pawl movement, and a reliably uniform leak-free 'operat'ion'is obtained.

l V The length of thermoplastic adhesive in solid rope or rod form 'illustratively shown at A is of a type that is supplied in octagonal or other cross-sectional form the a a passage in member 26, or at least its rearportion will be made to conform to that shape. Most, if not all, the thermoplastic adhesive formulations expand upon melting. The grooves a in effect enlarge the capacity of the passages in members 24 and 26 in proportion to.. the a volume of solid adhesive moving in the passages forwardly of the restricting screw-points As the pressure builds up in chamber 22 and the adjacent portion of the passage 23, liquified, or partially liquified adhesive will be forced back along the grooves a. As will be obvious the same elfect will be obtained by providing longitudinal grooves in the wall of the passage in member 26, beyond the points b, or otherwiseincreasing the crosssectional dimensions of that portionof the passage. In either case the back flow of heated material which tends to warm the incoming length of solid adhesive, and the differential in the heat supplied by'the heaters 6 and 40 will be adjusted accordingly.

The recesses 20 presented opposite chamber 22 form part of the volumetric capacity of the chamber. As the recesses 20 enter the chamber empty, and fill with liquid adhesive a drop in pressure results, and this'drop, while slight, may, in conjunction with'a drop in pressure during the rearward movement. of the feeding pawl or from. other causes such as temperature fluctuations or theffact that because of the speed'of rotation of the roll theair in the entering empty pockets may not be completely displaced by uniform pressure in the chamber, result in an incomplete filling of one of more of'the recesses- 20' before they leave the chamber. This danger is avoided by the bathe 95, the narrowing of the space between the baffle and the adjacent face of the roll which assures proper filling of the recesses under the operating conditions established by the previously described adjustments. It will also be understood that the. pressure exerted by the pawl springs S-Z'be adjusted by screws 54 to provide the needed feeding and holding gripof the pawls on the solid adhesive.

As illustrated the bracket 8 is formed with a saddle member 111 which seats on a frame member F of a tray forming machine by means of a strap plate 112 which clamps the bracket 8 to the frame member by screws 113.

As indicated in Fig. 1 an applying device may be mounted adjacent each corner of the mandrel M of a tray machine, and it will be understood that the device of the invention may be similarly used in various container forming, carton or bag closing or wrapping machines.

What is claimed is:

1. An adhesive applying device comprising a housing, an adhesive applying roll rotatably mounted in the housing for rotation free of peripheral contact therewith and having a portion of its peripheral surface extending outwardly of the housing, the peripheral surface of the roll being relieved to provide a plurality of recesses separated from each other and the peripheraledges of the roll by unrelieved portions of said surface, a plunger mounted in the housing and having an arcuate surface engaging and conforming to a portion of the peripheral surface of the roll within the housing, a passage extending longitudinally through said plunger for supplying adhesive to the peripheral portion of the roll. exposed therein, means yieldingly urging the portion of said arcuate surface surrounding said passage against the unrelieved portions of the peripheral surface of the roll, the said portions of said arcuate surface being of sulfirotation of the roll.

1... '..r.. 6 .2 cient extent to cdnfine the adhesive carried by the rollto said recessesgmeans to supply a solid length'of adhesive to the outer end of said passage, the outer end portion, at least, of said passage substantially conforming in cross sectional shape and dimensions to the cross sectional shape'and dimensions of the length of adhesive, means to heat the roll and thepnrtion of said passage adjacent thereto toa temperature to liquify the adhesive, oscillating means applyingyielding pressure to the length of solid adhesive outwardly of said passage to advance the length into and along said passage andapply hydraulic pressure to the liquified adhesive in the forward portion of the passage, and means to adjust the yielding pres-,

sure applied by said oscillating means to said solid length of adhesive whereby the stroke of said oscillating means is automatically reduced in response to a predetermined rise in the hydraulic pressure of the liquified adhesive to thereby maintain said hydraulic pr'essure constant. A 4

2..An adhesive applying device as in claim 1 having a baffle extending transversely of said passage adjacent the roll, the face of said baffle adjacent the roll being inclined to provide a narrowing passage between the.

opposed faces of the baffle and roll in the direction of 3. An adhesive applying device as in claim 1, the rear; portion of saidpassage being heat insulated from the forward portion to maintain that portion of the length of adhesive which is in said rear portion of the passage in a so lid condition.

4. An adhesive applying device asin claim -3,- the rear portion of said passage being in the form of a tubu lar extension coupled to the plunger by a heat insulatingcoupling.

5. Anadhesive applyingdevice as in claim 4 having means to heat said tubular extension to a temperature. only sufiicient to soften the surface of the length of adhesive passing therethrough to effect a lubrication of thewall surface of the passage through said extension.

6. An adhesive applying device comprising a housing, I

, housing for rotation free of peripheral-contact therewith and having a portion of its peripheral surface extending outwardly of the housing, the peripheral surface of the roll being relieved to provide a plurality of recesses separated from each other and the peripheral edges of the roll by unrelieved portions'of said surface, a plunger mountedin the housing and having an arcuate surface engaging and conforming to a portion of the peripheral surface of the roll within the housing, a passage extending longitudinally through said plunger for supplying adhesive to the peripheral portion of the roll exposed therein, means. yieldingly urging the portion of said arcuate surface surrounding said passage against the unrelieved portions of the peripheral surface of the roll, the-said portions of said arcuate surface being of sufficient extent to confine the adhesive carried by the roll to said recesses, means to' supply a solid length of adhesive to the outer end of said passage, the outer end portion, at least, of said passage substantially conforming in cross sectional shape and dimensions to the cross sectional shape and dimensions of the length of adhesive, means to heat the roll and the portion of said passage adjacent thereto to a temperature to liquify the adhesive, an oscillating pawl engaging the length of solid adhesive outwardly of said passage, spring means to advance the pawl and thereby advance the length into and along said passage and apply hydraulic pressure to the liquified portion of the adhesive in the forward portion of the passage, a cam member limiting the forward movement of the pawl and returning it to its rearward position, the forward stroke of the pawl permitted by. the cam being automatically reduced when the hydraulic pressure of the liquid adhesive exceeds the power of said spring, and holding means preventing retrograde movement of the 7 means to adjust the power of said spring.

7. An adhesive applyingfdevic'eas inclaimfifthe rear portionof said passagefbeingfin the form'of a' tubularf extension coupled to the plunger by a heat insulating coupling.

8. An adhesive applying device asin claim 6 having 7 9. An adhesive applying device as in claim 8 having means to adjust the length of stroke permitted the pawl by the cam. r

10. An adhesive applying device as in claim 9, said cam being a rotary cam and means 'to drive said roll and cam in timed relation. V V

ll. An 1 adhesive applying device as in claim- 10, the

cam being angularly adjustable to vary the dwell of the pawl in its forward and rear positionsa 12. An adhesive applying device comprising a housing, an adhesive applying roll rotatably mounted in the housing for-rotation free of peripheral contact therewith and having'a portion of its peripheral surface extending outwardly of the housing, the peripheral surface of the roll being relieved to provide a plurality of recesses sepa rated'from each other and the peripheraledgcs of the roll by unrelieved portions of said surface, a plunger and apply hydraulic pressure to the liquified portion of the adhesive in the forward portion of the passage, a cam member limiting the forward movement of the pawl and returning'it to its rearward position, the forward stroke of the pawl permitted by Qth e cam being automatically reduced when the hydraulic pressure of the liquid adhesive exceeds the power of said spring, holding means preventing retrograde movement ofgthe length of adhesive during the rearward movement of the pawl, and means, operating independently of said heating means, to raise the temperature of the surface only of said length of solid adhesive to effecta lubricated movement of said length through said tubular extension;

13. An adhesive applying device comprising a housing, an adhesive applying roll rotatably mounted'in the housing and having a peripheral portion extending outwardly of the housing, saidjhousing including a member making. a fluid tight engagement with an arcuate portion of the peripheral surface of the roll within'the housing,

said member being providcdwith a passage extending therethrough and openingfat onetend outwardly of the housing and at the other end to the said engaged pe- ,ripheral surface portion of the roll, means to supply a solid length of adhesive to the outer vend of said passage,

mounted. in the housing and having an arcuate surface engaging and conforming to a'portion 'of-the peripheral surface of the roll within the housing, a passage extending longitudinally through said plunger for supplying adhesive to the peripheralportion of the roll exposed therein, means yieldingly urging the portion of said arcuate surface surrounding said passage against the unrelieved portions of the peripheral surface of the roll, the said portions of'said'arcuate surface being of sufficient extent to confine the adhesive carried by the roll to said recesses, means to supplya solid length of adhesive to the outer end of said passage, the outer end portion, at least, of said passage substantially conforming in cross sectional shape and dimensions to'the cross sectional shape and dimensions of the length of adhesive, meansto heat the roll and theportion of said passage adjacent thereto to, V V a temperature to liquify the adhesive, the rear portion of said passage comprisingga tubular extensioncoupled to,

the plunger by a heatinsulating coupling, an oscillating pawl engaging the length of solid adhesive outwardly of said passage, spring means to advance the pawl and thereby advance the length into and along said passage the outer end portion, at least, of said passage substantially conforming in cross sectional shapeand dimensions to the cross sectional shape and dimensions of the length of adhesive, means to heat said roll andsaid passage adjacent thereto to a temperature to liquifythe adhesive, the peripheral surface of said roll being provided with a plurality of recesses spaced from each other and the peripheral edges 'ofthejroll, means to apply'pressure to the'length of solid adhesive in the direction of said roll,

and means actuating said pressure applying means to inalong said passage a distance determined by the hydraulic pressure of the liquid adhesive between said roll and the the latter,

7 References Cited in the file of this patent UNITED STATES PATENTS 2,399,688 Metzner et al. May], 1946, 2,783,735 Paulsen Mar. 5, 1957 ;2,7s7,241

Kelley Apr. 2, 1957 termittently advance said length of adhesive into and,

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