US3347205A

US3347205A - Adhesive applying device

Info

Publication number: US3347205A
Application number: US398497A
Authority: US
Inventors: Geoffrey F Dobbyn
Original assignee: Pneumatic Scale Corp
Current assignee: Pneumatic Scale Corp
Priority date: 1964-09-23
Filing date: 1964-09-23
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17

Description

5 Sheets-Sheet 1 Filed Sept. 23, 1964 INVENTOR. eoffrey F Dobbyn 1967 G. F. DOBBYN ADHESIVE APPLYING DEVICE 5 Sheets-Sheet 2 Filed Sept. 23, 1964 INVENTOR. fey/ Dobbyn ed, ("M

| I" l I l TTOE/YEY Oct. 17, 1967 G. F. DOBBYN 3,347,205

ADHESIVE APPLYING DEVICE Filed Sept. 23, 1964 5 Sheets-Sheei 5 M s M INVENTOR. Geoffrey l-TDobbyn BY GL -MQ W ATTO/Z/YE'Y Oct. 17, 1967 G. F. DOBBYN ADHESIVE APPLYING DEVICE 5 Sheets-Sheet Filed Sept. 25, 1964 IN VENTOR Geoffrey FDabbyn BY {MeL M A T7OENEY United States Patent Ofilice 3,347,205 Patented Get. 17, 1967 3,347,205 ADHESIVE AIPLYING DEVICE Geoffrey F. Dohbyn, Braintree, Mass., assignor to Pneumatic Scale Corporation, Limited, Quincy, Mass., a corporation of Massachusetts Filed Sept. 23, 1964, Ser. No. 398,497 Ciairns. (Cl. 118-7) ABSTRACT OF THE DISCLOSURE A device for applying quick-setting adhesive to the carton closing flaps of a filled carton. Liquid adhesive is transferred to a heated applying roll from a heated melt chamber which receives its supply in solid form. Control means detects depletion of adhesive in the supply to replenish the same.

This invention relates to an adhesive applying device particularly adapted for use in a packaging machine.

The invention has for an object to provide a novel and improved adhesive applying device of the character specified having novel provision for automatically maintaining a substantially uniform supply of adhesive in response to the demand therefor.

The invention has for a further object to provide a novel and improved adhesive applying device particularly adapted for handling a quick-setting adhesive, such as a microcrystalline wax emulsion wherein solid pellets of adhesive are automatically fed into a melting chamber to provide a substantially uniform supply of liquefied adhesive in response to the demand therefor.

Vv ith this general object in view and such others as may hereinafter appear, the invention consists in the adhesive applying device and in the various structures, arrangements and combinations of parts hereinafter described and particularly defined in the claims at the end of this specification. I

In the drawings illustrating the preferred embodiment of the invention:

FIG. 1 is a side elevation of the present adhesive applying device shown as embodied in a packaging machine having provision for closing and sealing the top closing flaps of a carton;

FIG. 2 is a plan view of the device, some of the parts being shown in cross section;

FIG. 3 is an end view partly in cross section of the device as seen from the left hand side of FIG. 1;

FIG. 4 is a plan view of a carton showing the side closin g flaps extended laterally and the end closing flaps folded inwardly, three of the flaps being provided with spots of adhesive as applied by the present device;

FIG. 5 is a front elevation of the same showing the applying roll;

FIG. 6 is a wiring diagram of a control circuit to be described; and

FIG. 7 is a cross sectional detail view of the glue pot on an enlarged scale showing the melting chamber and adhesive transfer mechanism supplying adhesive to the applying roll.

In general, the present invention contemplates a novel adhesive applying device particularly adapted for use in a packaging machine, herein shown as arranged to apply adhesive to selected top closing flaps of a filled carton, which flaps are thereafter closed into adhesive engagement to seal the top closure. Prior to the present invention a liquid type of adhesive having a relatively slow setting or drying time was used. As a consequence it was required to pass the carton through an elongated dryer which consists of spaced upper and lower belts between which the ends of the cartons are supported and advanced to hold the adhesively coated flaps down a suflicient length of time to permit the adhesive to dry to set the seal. With the advent of high speed packaging machinery the length of the dryer had tobe increased to unwieldly proportions to allow suflicient time to permit the adhesive to set.

In accordance with one feature of the present invention, in order to reduce the drying time and consequently the length of the dryer, or to eliminate entirely the need for a dryer in a high speed packaging machine, provision is made for applying to the top closing flaps a quick-setting hot melt adhesive, such as a microcrystalline waX emulsion which is capable of drying and setting up quickly after the flaps are closed and slight pressure applied for a relatively short time to provide an efficient top closure seal.

In practice, the hot melt adhesive must be kept at a relatively high temperature, about 350 F., to maintain it in a liquefied form sufiicient to prevent thickening and to permit easy handling during transfer from the supply to the adhesive applying roller and from the latter to the carton flaps. The hot melt adhesive also has a relatively high setting or hardening temperature, which is about 200 F. Furthermore, in a high speed packaging machine, capable of producing sealed containers at the rate of about containers a minute, for example, the supply of adhesive is rapidly depleted so as to require constant attention by the operator to replenish the supply.

In accordance with another feature of the present invention provision is made for automatically replenishing the supply of adhesive in response to the demand therefor. In the illustrated embodiment of the invention, the hot melt adhesive is supplied in a solid form, such as in the form of pellets, which may be fed at a uniform rate to a melting chamber to liquefy the adhesive. The liquefied adhesive is arranged to flow from the melting chamber into an adhesive supply chamber. The supply chamber is provided with means for detecting the height of the liquid adhesive in the chamber, and when the height of the liquid is reduced below a predetermined level provision is made for initiating the feed of the pellets into the melting pot. Conversely, when the height of the liquid in the adhesive chamber is increased to said predetermined level the feed of the pellets is discontinued.

Referring now to the drawings, in general the present adhesive applying device comprises an adhesive supply hopper 10 arranged to supply adhesive in the form of solid pellets 12 to a vibratory feeder indicated generally at 14. The vibratory feeder 14 is arranged to feed the pellets in a uniform stream into a heated melting chamber 16 mounted on a casing 18 above an adhesive supply chamber 20. The bottom wall of the melting chamber 16 is perforated as indicated at 21 so that the liquefied adhesive will flow from the melting chamber through the perforations and into the liquid adhesive chamber. The liquid adhesive is transferred from the chamber 20 onto an applying roll 22 by a transfer wheel 24 and a spreader roll 26. The applying roll 22 is continuously rotated in timed relation to the advance of the cartons 28 along a conveyer 30, and selected of the top closing flaps of the cartons are provided with spots of adhesive during the continuous movement of the cartons.

As illustrated in FIGS. 2 and 3, provision is made for sensing the height of the liquid in the liquid adhesive chamber 26 by detecting means indicated generally at 32, and a photoelectric switch 34 actuated by movement of the detecting means and included in a circuit to the vibratory feeder 14 is arranged to control the pellet feeding operation in response to the demand for adhesive.

The conveyor 30 along which the cartons are sup ported advanced may form a part of a packaging machine, such as top closing machine, wherein the cartons are supported by stationary bottom rails 36 and side rails 37 and are advanced by spaced pusher arms 38 carried 1 by a continuously moving metal belt 40. As herein shown, the metal belt 40 is supported in a grooved track 42 formed by upper and lower extension bracket 44, 4-6 attached to the machine frame in a manner similar to that shown and described in the United State patent to Bergeron et al., No. 2,996,855, issued Aug. 22, 1961, to which reference may be made, As also illustrated and described in the Bergeron et al. patent, prior to being advanced into operative relation to the adhesive applying roll 22 the carton closing flaps are folded to assume the condition shown in FIG. 4 wherein the

side Wall flaps

48, 50 are spread outwardly at right angles to the top of the carton, and the

end wall flaps

52, 54 are folded inwardly on top of the carton. The flaps are maintained in such folded condition during the advance of the carton to the adhesive applying roll 22 by suitable guide rails 56.

The adhesive applying roll 22 which is rotated at a peripheral speedequal to the linear speed of the cartons is provided with a plurality of conical openings arranged in a pattern as shown in FIGS. 4 and 5, the conical opening carrying adhesive so that when the carton is advanced into operative relation to the roll selected 'of the carton flaps will be provided with spots of adhesive. It will be understood that the remainder of the applying roll, is scraped free of adhesive as will be described. As indicated in FIG. 4, the

end wall flaps

52, 54 folded on top of the filled carton will be provided with adhesive spots 58, 6t and the remaining side wall flap 48 will be provided with adhesive spots 62, the remaining side wall flap 50 being free of adhesive. Pressure of the applying roll 22 against the top of the filled carton is suflicient to effect transfer of the glue from the conical openings to the

end wall flaps

52, 54. However, the laterally extended side wall flap 48 is supported on its underside by a roller 64 carried by an arm 66 pivotally mounted at 63 in a bracket 70 secured to a plate 76 extending from the underside of a supporting bracket 77. A second arm 72 integral with the arm 66 is arranged to be urged downwardly so as to cause the roller 64 to press upwardly toward the applying roll 22. As shown herein, a stud 74 extends through a clearance opening in the arm 72, the stud being threadedly secured in a lateral extension 75. A compression spring 73is coiled about the stud between the upper face of the arm 72 and the underside of the extension 75. The head of the stud 74 limits the downward movement of the arm 72. It will be observed that the pressure roller 64 is provided with a grooved portion 84 which straddles the row at conical adhesive applying openings 63 in the roll 22 so that the roller 64 will not pick up adhesive when no cartons are passing through.

After the adhesive spots have been applied to the flaps, as described, the adhesive-free side wall flap 59 is first folded over on top of the

end wall flaps

52, 54 to be adhesively secured thereto by the adhesive spots 58, 6t]. Thereafter, the remaining side wall flap 48 is provided with the adhesive spots 62 is foldedover on top of the adhesive-free .flap to adhesively secure the last' folded flap. The flap closing operation may be performed during the continued movement of the carton by stationary curved folding rails indicated at 86, 88 in a conventional manner, as shown in FIG. 1, and as also shown in the Bergeron et al. patent above referred to. After the flaps have been closed, pressure may be applied to the top of the carton in any usual or preferred manner, such as by pressure rolls 89 arranged in the path of the cartons.

As shown in FIG. 2, the adhesive applying roll 22 is arranged to be rotated in timed relation to the movement of the cartons through connections adapted to be driven from the packaging machine. The roll 22 is keyed to one end of a shaft 9t), the other end of the shaft being connected by

bevel gears

92, 94 to a shaft 96 arranged to be driven through a chain and sprocket drive 98 connected to a drive shaft of the packaging machine, not shown.

Referring now to FIG. 1 for a more detailed description of the pellet feeding mechanism, the vibratory feeder 14 is arranged to receive the solid pellets of adhesive 12 by gravity from the supply hopper 10 as controlled by an adjustable plate 100 secured to the front wall of the hopper outlet. The vibratory feeder may be of the type capable of feeding a substantially uniform stream of pellets at a constant rate of speed and, as herein shown, may comprise a horizontally extended trough 102 supported by thin flexible metal straps or leaf springs 104 secured to a platen 106 extended from a frame member 168. The trough 102 is arranged to be vibrated by a vibratory motor 110 which is also securedto the platen 106. The vibratory motor 110 is included in a circuit shown in FIG. 6 which also includs a rheostat RHI and a rectifier RECI, and the motor is arranged to be automatically started and stopped in response to the demand for adhesive as will be described.

It will be observed that the outlet end of the trough 162 is provided with a depending lip 112. In operation, prior to the addition of the lip 112, some of the pellets at the front edge of the bottom wall of the trough which might be presoftened by the heat rising from the melting chamber 16 would have a tendency to stick to such front edge, and the provision of the depending lip 112 .was found to be conducive to a free flow of the pellets. The pellets 12 discharged from the outlet end of the trough 102 fall by gravity through a funnel 113 and into the mein-g chamber 16. As herein shown, the melting chamber 16 is heated by thermostatically controlled

heating cartridges

114, 116 which extend into the relatively thick chamber walls 118, 120. A thermostat indicated at T53 in FIG. 3 is also extended into the chamber wall 118for controlling the heat of the melting chamber. The solid pellets 12 are liquefied in the melting chamber, and the liquid adhesive flows through the openings 21 in the bottom wall of the melting chamber and into the liquid adhesive chamber 20.

As illustrated in FIG. 3, the liquid chamber 20 is elongated and provided at one end, immediately below the melting chamber 16, with a relatively thick inclined wall 122 down which the melted adhesive flows into a well portion 124 of the liquid chamber where the adhesive is accumulated and from which the adhesive is picked up and transferred to the applying roll 22. The relatively thick inclined wall 122 is also heated by

cartridge heaters

126, 128 and 130 which extend through the wall, and a cartridge heater 132 is disposed in a thickened portion 133 at one corner of the well portion 124. A thermostat TS2 extended into the lower end of the inclined wall 122 is provided for controlling the temperature of the liquid chamber 20.

As shown in FIG. 7, the adhesive pickup wheel 24 comprises a relatively thin plate having a plurality of radially extended arms 136 which dip into the liquid adhesive as the wheel is rotated and transfer a relatively small amount of liquid adhesive onto the spreader roll 26. T he spreader roll 26 is rotated in close contact with the applying roll 22 and in cooperation with the latter spreads an even film of adhesive over the entire area of the applying roll and fills the

conical openings

63, 65 in the roll with adhesive, the film of adhesive being subsequently scraped ofi clean,

leaving the adhesive in the conical openings. As illustrated in FIGS. 2 and 3, the spreader roll 26 is driven from the shaft 90 through

spur gears

140, 152, the latter being fast on the spreader roll shaft 144, and the pickup wheel 24 is rotated by a spur gear 146 on the shaft 144 which is in mesh with a spur gear 148 fast on the pickup wheel shaft 150.

As illustrated in FIG. 2, the adhmive applying roll 22 extends forwardly of the liquid adhesive chamber 20 and is embraced at its upper end by

side scrapers

152, 154 extended forwardly from the adhesive chamber. The side scrapers serve to contain the adhesive from leaking over the sides of the roll and also serve to guide the surplus adhesive back into the liquid adhesive chamber. The side scrapers may be adjustably mounted to fit snugly against the sides of the roll as shown. The face of the applying roll 22 is arranged to be scraped substantially free of adhesive by an adjustable scraper bar 156 which meets the face of the roll at an angle providing a pocket 153 defined by the periphery of the roll and the end of the scraper bar. This expedient serves to scrape the face of the roll clean without reducing the amount of adhesive retained by the

conical openings

63, 65 so as to effect eflicient application of the spots of adhesive to the carton flaps as described. The scraper bar 156 extends the full width of the roll 22 and cooperates with the

side scrapers

152, 154 to return the surplus adhesive to the liquid chamber.

Referring now to FIG. 2, provision is also made for heating the applying roll 22. As herein shown, the applying roll is hollow and is provided with an elongated hollow sleeve 160 mounted for rotation in a bearing formed in the bracket 77. The bracket 77 is secured to a supporting bracket 108 attached to the machine frame. A coiled heating tube 164 is disposed within the hollow portion of the applying roll 22, and the ends thereof extend through and are supported within an elongated stationary sleeve 166 extended within the rotary sleeve 160. The stationary sleeve 166 is formed integrally with a flange 168 which is bolted to the bearing bracket 77. A housing 170 also formed integrally with the flange 168 is provided for mounting and connecting the terminals of the heating tube 164. Thus, in operation, the applying roll 22 is maintained in a heated condition during the application of adhesive to the carton flaps.

As shown in FIGS. 1 and 2, a supporting bracket 175 attached to the bracket 168 extends over the top of the applying roll 22, and extensions therefrom serve to support the spreader roll 26 and the

side scrapers

152, 154. The expedient of mounting the spreader roll and the scrapers so as to be supported above the applying roll and independently of the adhesive chamber 20 permits the casing 18 to be disassembled and removed for clean ing purposes with minimum interference. It will be observed that the spreader roll shaft 144 is journaled in eccentric bearings 178, 180 mounted for rotary adjustment to adjust the spreader roll 26 relative to the applying roll 22. Also, the upper wall of the bracket 175 is provided with an opening covered by a hinged door 176 for convenience of the operator to examine the condition of the adhesive during the operation of the machine. As also indicated in FIGS. 1 and 2, the pickup Wheel 24 is provided with a housing 177 mounted within the casing 18 as shown.

Referring now to FIGS. 2 and 3, the control mechanism 32 for controlling the feed of the pellets in response to the demand for adhesive includes a hollow ball 184 which floats in the adhesive in the Well portion 124 of the liquid adhesive chamber 20. The ball is connected to one arm 186 of a two-armed lever pivotally mounted between trunnion screws 138, 190. As illustrated, the arm 186 extends through a clearance opening in the chamber casing 18. The second arm 192 of the two-armed lever is arranged to cooperate with the photoeleectric switch indicated at 34 which includes a photocell 194 and a light source 196. The arm 192 is provided with a plate 198 arranged to intercept or cut off the beam of light. The photoelectric switch 34 is included in the circuit to the vibratory motor 110, as shown in the wiring diagram, FIG. 6, and in operation when the adhesive is depleted below a predetermined level in the well portion 124, the plate 198 is moved out of the path of the light beam, at which time the vibratory motor 110 is energized to start the feeding operation. Conversely, when the level of the adhesive is restored to a predetermined higher level, the plate 198 will be moved to intercept the light beam to deenergize the vibratory motor and discontinue the feeding operation.

As illustrated in FIG. 6, one circuit indicated at 290 comprises a part of the main drive motor circuit, and another circuit indicated at 202 indicates the vibratory motor circuit which includes the photoelectric switch 34. The vibratory motor circuit 262 also includes relay contacts M1 which are closed when the main machine motor is started by pressing push button PBI. The vibratory motor circuit 262 further includes a switch SSW3 having contacts 268 in the main motor circuit 290 and contacts 21d in the vibratory motor circuit 262. The switch SSW3 is arranged to be operated to open the contacts 208 in the main motor circuit and close the contacts 210 in the vibratory motor circuit by manual operation of a clutch, not shown, connecting the drive from the main machine to the chain and sprocket drive connection 98. As illustrated, a by-pass line 212 in the main motor circuit is provided with a switch SSW8 to continue the circuit to the main motor M1 when the contacts 208 of switch SSW3 are opened.

The vibratory motor circuit 202 is energized through lines 2193 and 2115. Line 203 is provided with a manually operated switch S5 which is connected to line 207, the circuit being continued through contacts 210 and M1 to one line 269 leading to the light operated photoelectric relay PE. A second line 211 leading from the relay PE is connected to a manually operated switch S4 in line 204 which leads to the vibratory motor 110. A return line 213 from the vibratory motor leads to the line 205, as shown, to complete the circuit.

From the description thus far it will be seen that in operation the vibrator motor is automatically started When the float ball 184 moves to a lowered position to rock the plate 198 out of the path of the light beam, and conversely, when the float ball rises, the plate is rocked into the path of the beam to discontinue the feed of the adhesive pellets. A manually operated switch PB6 in line 215 is provided for convenience to operate the vibrator motor in response to a demand for adhesive when the clutch operated switch SSW3 is opened. It will be seen that closing of switch P86 will operate the vibrator independently of the operation of the main machine when the relay PE is energized. The switch S4 comprises a toggle switch for convenience of the operator to discontinue the feed of pellets when desired. It will also be observed that if the light source or relay fails the vibrator feed will not operate.

The switch SSW8 comprises an overload safety switch arranged to be opened to open the circuit to the main motor in the event that an overload occurs in the drive to the adhesive applying roll. As illustrated in FIGS. 2 and 3, the chain and sprocket drive 28 is connected to the shaft 96 by a separable drive connection or overload safety arranged to be disengaged in the event of an overload. The sprocket of the drive connection is formed integrally with a disk 216 and is mounted to rotate freely on a sleeve 218 keyed to the end of the shaft 96. The outer end of the sleeve 218 is provided with a head 220 having a notch 222 out in the periphery thereof. A drive lug 224 carried by an arm 226 pivotally mounted at 228 is spring urged into engagement with a notch 222. The side walls of the notch and the drive lug are tapered as shown so that in the event of an overload the lug will be forced out of driving engagement with the notch. In order to hold the lug carrying arm 226 in its outwardly rocked position so that the lug will not reengage with the notch upon completion of one revolution, a spring urged hooked member 230 is arranged to engage a latch member 232 carried by the lug carrying arm 226 when the latter is rocked out of driving engagement. The hook member 230 is provided with a handle 234 for manually releasing the latch 232 after the overload condition has been corrected.

As shown in FIG. 2, the switch SSWS is disposed adjacent the overload safety drive connection and is provided with an arm 236 which carries a roller 238 arranged to be engaged by a portion 240 of the lug carrying arm 226 when the latter is rocked out of driving engagement and continues its rotation to engage the roller 23%. The switch SSWS is normally in its closed position and when engaged by portion 240 is opened to open the circuit to the main drive motor as described.

The circuits to the heating elements in the melting chamber, the liquid chamber and the adhesive applying roll will now be described. As illustrated in FIG. 6, the

heating elements

114, 116 in the melting chamber are energized through lines 2%, 295 as controlled by a thermostat T53 upon closing of manually operated switch S2 in line 203. The circuit is continued through

lines

242, 244, thermostat T83 and

elements

114, 116. Line 246, leading from the elements, is connected to the return line 295 as shown. The

elements

126, 128, 130, 132 are also energized through lines 203, 265 as controlled by thermostat TS2 and relay MCZ. A line 248 from switch S2 is connected through the thermostat T52 to the relay MC2, the circuit being completed through return line 205. Energization of relay MCZ will effect closing of contacts MC2 in line 259 to energize the

heating elements

126, 128, 130, 132 as shown.

The heating coil indicated diagrammatically at 164 in FIG. 6 and which is disposed within the hollow adhesive applying roll 22 is arranged in the circuit to maintain a relatively high heat during operation of the device and to maintain a relative low heat when the device is temporarily idled or stopped. It will be understood that in operation all of the heating elements are activated a considerable period of time prior to starting the packaging machine in operation for the purpose of heating the adhesive to the proper temperature to permit a free flow of the same. During the preliminary warm up time, prior to starting the adhesive applying operation, it is preferred to maintain the applying roller 22 at a low temperature so that burning or charring of the adhesive in engagement with the roll is avoided. Thereafter, when the machine is started and the adhesive applying device is activated it is preferred to maintain the applying roll at a high temperature. During operation of the device with the roll at a high temperature, some of the heat is dissipated upon engagement of the roll with the carton flaps so that charring or burning of the adhesive in contact with the roll is avoided.

As illustrated in FIG. 6, when the machine is idle, that is, when the switch contacts 210 of switch SSW3 are open, as shown, the heating coil 164 is heated through a variable autotransformer AT2, the transformer being connected to the heating coil through normally closed relay contacts MC3. The lines to the transformer AT2 include line 203 through switch S5 and line 207 to line 252 connected to one end of the transformer, the other end thereof being connected by line 254 to the return line 213. The connection from the transformer AT2 to the heating coil 164, comprises a line 256 in which the normally closed contacts MC3 and the coil 164 are connected, the coil being also connected to the return line 213.

When a sufficient time has elapsed to effect preheating of the adhesive applying device, the clutch is operated to close the contacts 210 of switch SSW3, and the main machine motor is started. Upon closing of the contacts 210 a relay MC3 in line 215 is energized which operates to open normally closed contacts MC3 in low heat transformer circuit and to close the normally open contacts MC3 in the circuit of a second variable autotransformer AT3 adjusted to maintain a high temperature of the roll 22. The transformer ATS is connected by a line 258from line 207 and by a line 260 to the return line 213. The heating coil 164 is thus automatically connected to the high heat transformer AT3 by line 262 in which the normally open contacts MC3 are located. Conversely, when the clutch to the chain and sprocket drive 98 is disengaged and the contacts 210 of switch SSW3 are opened, the relay MC3 will be deenergized and the coil 164 will be automatically connected in the circuit to the low heat trans former AT2. As also shown in FIG. .6, a signal lamp LT2 is provided in the vibrator circuit to indicate to the operator that the vibratory motor circuit is energized.

From the above description it willbe seen that the present adhesive applying device for a high speed packaging machine is adapted to apply a quick-setting adhesive to the top closing flaps of a carton during the continuous movement thereof so that when the adhesively coated flaps are closed in overlapping relation they are quickly set in sealed engagement to provide an efiicient top closure, the advantage being that the usual elongated dryer for holding the flaps in sealing engagement until the seal is set is eliminated, resulting in a considerable saving of the space required for the dryer. It will be further seen thatthe present device provides novel means adapted to automatically feed adhesive to the device in response to the demand therefor as the adhesive is used up whereby to eliminate manual addition of adhesive to the supply.

While the preferred embodiment of the invention is herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is: 1. In a packaging machine, in combination, conveying means for supporting and continuously advancing filled cartons having their top flaps arranged to receive adhesive, adhesive applying means for applying a hot melt adhesive to selected of said flaps during the continuous r movement of said cartons, said adhesive applying means comprising a continuously rotated and heated adhesive applying roll, a heated supply chamber containing a supply of melted adhesive, means for transferring the melted adhesive from the supply chamber to the applying roll for application to said carton flaps, a heated melting chamber having a perforated bottom wall in communication with said supply chamber, means for feeding hot melt adhesive in solid form to said melting chamber to melt and flow into said supply chamber, and control means including means for detecting a depletion in the amount of adhesive in said supply chamber, and means responsive to said detecting means for actuating said feed- 1 ing means to restore the amount of adhesive in said supply chamber, said feeding means comprising a vibratory feeder having a vibratory motor, a circuit for said vibratory motor, said control means including a normally open switch in said circuitarranged to be closed upon detection of a depletion in the amount of adhesive in said supply chamber, a relay controlled main motor circuit for the packaging machine, and normally open contacts in said vibratory motor circuit arranged to be closed when the main motor circuit is energized, and a manually operated switch by-passing said normally open main motor circuit contacts for energizing said vibratory motor circuit independently of said main motor circuit.

2. A packaging machine as definedin claim 1 wherein said melting chamber is disposed above said supply chamber, and an inclined passageway between said chambers.

3. A packaging machine as defined in claim 1 wherein said adhesive applying roll is provided with patterned areas for applying adhesive onto selected areas of the flaps, and driving means for said adhesive applying ro-ll arranged to rotate the roll at a peripheral speed equal to the linear speed of said conveying means and in timed relation to the continuous movement of said cartons to effect registration of said patterned areas with the selected areas of said flaps.

4. In a packaging machine, in combination, conveying means for supporting and continuously advancing filled cartons having their top flaps arranged to receive adhesive, adhesive applying means for applying a hot melt adhesive to selected of said flaps during the continuous movement of said cartons, said adhesive applying means comprising a continuously rotated and heated adhesive applying roll, 'a heated supply chamber, means for transferring the melted adhesive from the supply chamber to the applying roll for application to said carton flaps, a heated melting chamber having a perforated bottom wall in communication with said supply chamber, means for feeding hot melt adhesive in solid form to said melting chamber to melt and flow into said supply chamber, control means including means for detecting a depletion in the amount of adhesive in said supply chamber, means responsive to said detecting means for actuating said feeding means to restore the amount of adhesive in said supply chamber, a heating circuit, a heating element for said applying roll, means for maintaining said element at a relatively low temperature when said applying roll is idle, and means for maintaining said element at a higher temperature when said roll is rotated, said low and high temperature means including a low heat transformer in connection with said heating element when the roll is idle, a high heat transformer in connection with said element when the roll is rotated, and means including a switch in said circuit arranged to be closed upon rotation of said roll for shifting the connection from said low heat to said high heat transformer.

5. In a packaging machine, in combination, conveying means for supporting and continuously advancing filled cartons having their top flaps arranged to receive adhesive, adhesive applying means for applying a hot melt adhesive to selected of said flaps during the continuous movement of said cartons, said adhesive applying means comprising a continuously rotated and heated adhesive applying roll, a heated supply chamber containing a supply of melted adhesive, means for transferring the melted adhesive from the supply chamber to the applying roll for application to said carton flaps, a heated melting chamber having a perforated bottom wall in communication with said supply chamber, means for feeding hot melt adhesive in solid form to said melting chamber to melt and flow into said supply chamber, and control means including means for detecting a depletion in the amount of adhesive in said supply chamber, and means responsive to said detecting means for actuating said feeding means to restore the amount of adhesive in said supply chamber, said solid adhesive being in the form of ellets, said feeding means comprising a vibratory feeder having a vibratory motor, a circuit for said motor, said control means including a normally open switch in said circuit, said detecting means comprising a float ball in said supply chamber, and connections to said float ball for operating said switch to initiate the feeding operation when the adhesive is depleted below a predetermined level, and to discontinue the feeding operation when the adhesive is restored to said level.

References Cited UNITED STATES PATENTS 2,301,136 11/1942 Moreland et al. 222-56 2,693,429 11/1954 Radtke et 211.

2,764,123 9/1956 Derderian 118216 3,030,915 4/1962 Shannon 118202 3,050,756 8/1962 Kamborian.

3,135,628 6/1964 Johnson et a1.

3,237,593 3/1966 Trotter 118-7 3,279,425 10/1966 Gottscho 118-261 CHARLES A. WILLMUTH, Primary Examiner.

R. I. SMITH, Assistant Examiner.

Claims

1. IN A PACKAGING MACHINE, IN COMBINATION, CONVEYING MEANS FOR SUPPORTING AND CONTINUOUSLY ADVANCING FILLED CARTONS HAVING THEIR TOP FLAPS ARRANGED TO RECEIVE ADHESIVE, ADHESIVE APPLYING MEANS FOR APPLYING A HOT MELT ADHESIVE TO SELECTED OF SAID FLAPS DURING THE CONTINUOUS MOVEMENT OF SAID CARTONS, SAID ADHESIVE APPLYING MEANS COMPRISING A CONTINUOUSLY ROTATED AND HEATED ADHESIVE APPLYING ROLL, A HEATED SUPPLY CHAMBER CONTAINING A SUPPLY OF MELTED ADHESIVE, MEANS FOR TRANSFERRING THE MELTED ADHESIVE FROM THE SUPPLY CHAMBER TO THE APPLYING ROLL FOR APPLICATION TO SAID CARTON FLAPS, A HEATED MELTING CHAMBER HAVING A PERFORATED BOTTOM WALL IN COMMUNICATION WITH SAID SUPPLY CHAMBER MEANS FOR FEEDING HOT MELT ADHESIVE IN SOLID FORM TO SAID MELTING CHAMBER TO MELT AND FLOW INTO SAID SUPPLY CHAMBER, AND CONTROL MEANS INCLUDING MEANS FOR DETECTING A DEPLETION IN THE AMOUNT OF ADHESIVE IN SAID SUPPLY CHAMBER, AND MEANS RESPONSIVE TO SAID DETECTING MEANS FOR ACTUATING SAID FEEDING MEANS TO RESTORE THE AMOUNT OF ADHESIVE IN SAID SUPPLY CHAMBER, SAID FEEDING MEANS COMPRISING A VIBRATORY FEEDER HAVING A VIBRATORY MOTOR, A CIRCUIT FOR SAID VIBRATORY MOTOR, SAID CONTROL MEANS INCLUDING A NORMALLY OPEN SWITCH IN SAID CIRCUIT ARRANGED TO BE CLOSED UPON DETECTION OF A DEPLETIN IN THE AMOUNT OF ADHESIVE IN SAID SUPPLY CHAMBER, A RELAY CONTROLLED MAIN MOTOR CIRCUIT FOR THE PACKAGING MACHINE, AND NORMALLY OPEN CONTACTS IN SAID VIBRATORY MOTOR CIRCUIT ARRANGED TO BE CLOSED WHEN THE MAIN MOTOR CIRCUIT IS ENERGIZED, AND A MANUALLY OPERATED SWITCH BY-PASSING SAID NORMALLY OPEN MAIN MOTOR CIRCUIT CONTACTS FOR ENERGIZING SAID VIBRATORY MOTOR CIRCUIT INDEPENDENTLY OF SAID MAIN MOTOR CIRCUIT.