US3352279A

US3352279A - Adhesive applicator

Info

Publication number: US3352279A
Application number: US487527A
Authority: US
Inventors: Glynn H Lockwood
Original assignee: Lockwood Tech
Current assignee: Lockwood Technical Inc
Priority date: 1965-09-15
Filing date: 1965-09-15
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14

Description

NOV- 14, 1967 G; H. LocKwooD 3,352,279

ADHESIVE APPLICATOR Filed sept. l15, 1965 5 sheets-sheet 1 FIG-"l W7 ze INVENTOR 7 6L m//v oc/(M000 #fram/EK;

Nov. 14, 1967 G. H. LocKwooD 3,352,279

'ADHESIVE APPLIcAToR A Filed Sept. l5, v1965 Z Sheets-Sheet 2 /TCE` V- a3 m m29 4 52 FIG2 INVENTOR. 54m/N #flan/dana Nov. 14, 1967 G. HQ LocKwooD 3,352,279

ADHES I VE APPLI CATOR Filed Sept. 15, 1965 E Sheets-Sheet Z FIG-4 INVENTOR 6L mw M oc/(woop United States Patent O 3,352,279 ADHESIVE APPLICATOR Glynn H. Lockwood, Carmel, Calif., assignor to Lockwood Technical, Inc., a corporation of California Filed Sept. 15, 1965, Ser. No. 487,527 7 Claims. (Cl. 118-7) ABSTRACT OF THE DISCLSURE ble doctor blade on the reservoir engaging the applicator wheel.

My invention relates to devices for converting an adhesive in solid form into an adhesive in liquid form and for applying the liquid adhesive to a receiving member; for example, a carton blank.

In the packaging of foods in cartons, as well as in many other environments, it has become customary to apply adhesives in areas such as strips or dot patterns or the like to panels of the containers in order that the containers when erected will remain in the configuration desired.

The preferable adhesive for use under these circumstances is one which is solid under ordinary handling conditions and can be shipped, stored and utilized in its solid state. Iust prior to utilization on the carton blank, the adhesive is changed from solid to liquid form by being heated. One adhesive for this purpose is in the form of a circular cylinder several inches in diameter and a multiple of its diameter in length. Since this body looks something like a candle, it is often referred to as an adhesive candle.

It is an object of the invention to provide a machine for utilizing a solid body of adhesive and for converting that body into a liquid adhesive and then applying the liquid adhesive to an object to be coated.

Another object of the invention is to provide an adhesive applicator in which there is afforded a supply of liquid adhesive for an applicator wheel, especially Ifor an applicator wheel having a pattern on it.

Another object of the invention is to provide an adhesive applicator that in a controlled way and automatically converts adhesive from solid form into a suitable supply of liquid adhesive for application.

Another object of the invention is to provide an adhesive applicator in which a predetermined level of liquid adhesive is maintained for use by an applicator wheel.

A still further object of the invention is to provide an adhesive applicator in which the machine readily sets or adjusts itself to accommodate the adhesive applicator wheel.

Another object of the invention is to provide an automatic control system for an adhesive applicator so that the supply of adhesive is maintained at the desired rate. Another object of the invention is in general to provide an improved adhesive applicator.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIGURE 1 is a side elevation of an adhesive applicator constructed in accordance with the invention, various portions of the structure being broken away and disclosed in a cross section taken on a vertical plane;

FIGURE 2 is a plan of the structure shown in FIG- URE 1, portions being broken away to show the interior construction in cross section on a horizontal plane and a portion of the device being removed for clarity of disclosure;

FIGURE 3 s a cross section, the plane of which is indicated by the line 3-3 of FIGURE 2;

FIGURE 4 is an end elevation of the structure shown in the preceding figures;

FIGURE 5 is a cross section on a vertical plane showing a modified form of level sensing device; and

FIGURE 6 is a cross section, the plane of which is indicated by the line 6 6 of FIGURE 5.

While the adhesive applicator pursuant to the invention can be incorporated in a large number of different ways, depending in part upon the particular installation in which it is to be utilized, it has in practice been successfully embodied as disclosed herein.

in this environment the mechanism is designed for attachment to a bracket 6 forming part of a mechanism over which carton blanks 7, for example, are advanced in the direction of the arrow 8, the blanks being at at this stage. They receive on a convenient (here the upper) surface 9 thereof a sup-ply of liquid adhesive. Secured to the bracket 6 is a first frame 11 from the top 12 of which projects a collar 13 receiving an upstanding tube 14 forming the support for a control and display stand 16. This stand is a generally rectangular housing having

various indicators

17 and 18 thereon and having a manual control 19 for adjusting the temperature of the adhesive applicator. The control stand is the terminal point for an electrical supply lead 21 from any suitable source of electromotive force and serves also as the distributing point for various electrical connections and controls of the adhesive applicator.

The first `frame 11 serves as a journal mounting for a shaft 26 preferably of tubular form and designed to rotate about an axis 27. At one end, the shaft carries an overload or slipping clutch 28 interconnecting the shaft with a drive sprocket 29 joined to any suitable source of rotary power.

Fastened on the outboard end of the shaft 26 is an applicator wheel 31 having a rim 32, the outside portion 33 of which is designed to hold liquid adhesive. The portion 33 of the applicator wheel is preferably provided with a number of adhesive receiving depressions 34 in any desired pattern so that the adhesive deposit pattern is repeated once for each rotation of the applicator wheel as the applicator wheel comes into physical contact with the upper surface 9 of the blank 7.

Since the temperature of the applicator wheel is an important factor, there is provided in a drum extension on the first frame 11 and within the rim 32 a number of electrical heaters 37 connected by appropriate leads 38 to the source of electrical energy 21 within the enclosure 16. Thus, as the applicator wheel is revolved about the axis 27 by the drive force applied to the sprocket 29, the moving rim 32 is simultaneously heated and kept at the desired temperature.

The wheel rotates in juxtaposition with a bath of liquid adhesive. For that reason, there is provided an adhesive holding means. The holding means includes a generally C-shaped second frame 41 adapted to be spaced some distance from the periphery of the applicator wheel so as to leave an intervening reservoir 42 for liquid ad hesive. The frame 41 at either side carries separate plates 43 and 44 secured in position by fastenings 46. The plates bear tightly against the sides ofthe applicator wheel to preclude any substantial leakage of liquid adhesive between the plates 43 and 44 and the side faces of the applicator wheel.

The second frame 41 has a lower wall 47 extending close to but stopping short of the periphery of the applicator wheel. Disposed just below the wall 47 is a doctor blade 48. This is a relatively thin, springly metallic member held in position by a bottom strap 49 fastened by screws 51. The doctor blade is adjustable since it is perforated with elongated apertures to lie around the fastenings 51 for the bottom strap 49 and its edge is abutted by an adjusting screw 52 set in the second frame 41. With this arrangement, the adjusting screw can be tightened or loosened when the fastenings 51 are loose so as to move the doctor blade toward or permit it to retract from the surface of the applicator wheel. Once the desired adjustment has been attained, the screws 51 are tightened and the doctor blade 48 is held in position so that there is substantially no leakage between it and the applicator wheel.

The second frame 41 is movably mounted with respect to the first frame 11. This is accomplished by providing a sleeve 56 having one end yextending rotatably through an opening 57 in the C-shaped frame 41 and having its other end firmly seated in an opening 58 in the first frame 11. The sleeve is a circular cylindrical tube symmetrical about an axis 59. The second frame 41 can rock or twist about the axis 59 with respect to the first frame 11. In order to preclude leakage despite this relative rocking motion, an O-ring 61 is interposed between the second frame 41 and the sleeve 56. So that the relative rocking motion will not be entirely unrestrained and to afford good backing for the doctor blade 48, the first frame is provided with an adjusting screw 62 carrying a spring 63 urging a ball 64 against a face of the C-shaped frame 41. By adjustment of the screw 62 the ball 64, in riding on the second frame 41, imposes a force opposing the doctor blade thrust. The second frame 41 is thus appropriately located. With this pivotal or floating mounting of the second frame, a close fit of the plates 43 and 44 and of the doctor blade 48 is readily maintained despite slight variations in tracking of the wheel 31 due to various causes.

In order to supply liquid adhesive to the applicator Wheel rim 32, the first frame 11 has a thermally insulated extension 66 formed of metal but having a cover 6'7 of thermally insulating material held in place by fastenings 68. A tube 69 extends upwardly from the cover 67 and is enlarged to receive an insulating collar 71. Resting on the collar is a tube 72 of the requisite diameter and height to receive at least one candle 73 of solid adhesive material. The candle is a relatively loose fit within the tube 72 and at its bottom rests on a grid 74 spanning the insulating collar 71. The grid is connected through the insulating collar 71 by a tiexible lead 75 to the electrical energy supply Within the housing 16. The grid 74 is thus electrically energized under proper control to become heated and to melt the solid adhesive at the bottom of the candle 73. This melted adhesive falls by gravity from the grid and travels down through the tube 69 into a chamber 76 forming a receiving reservoir within the frame extension 66. When the grid 74 is operating, a pool 78 of liquid adhesive is provided within the chamber 76, being lmaintained liquid and at proper temperature by an electric heater 79 connected through a governing thermostat to the source of electricity within the enclosure 16.

So that a desired quantity of liquid adhesive will be maintained within the reservoir chamber 76, a temperature sensing probe 81 extends through the cover 67. The probe is fastened to a transverse support 82 acting as a heat sink and carried by a pair of heat radiating plates 83 secured to the first frame 11 by fastenings 84. The probe 81 extends to connections within the housing 16 and can be set by manipulation of a control 80 to be effective at any desired valve. When the probe 81 is out of contact with liquid adhesive, its temperature becornes relatively low. This factor controls the grid energization so that the grid 74 is heated and supplies additional liquid adhesive to the chamber 76. When the liquid adhesive level rises sufficiently to encompass the tip of the probe 8,1, the probe temperature is then brought up and the supply of energy to the grid 74 is interrupted. By this means, the level 78 is maintained at a desired point.

The supply of liquid adhesive in the reservoir 76 tiows by gravity through a passageway 86 (FIG. 2) into a transverse bore 87 continuing the passage 86 and opening onto an intersecting bore 88 in which the sleeve 56 is seated. In this way, the same level 78 maintained in the chamber 76 is also maintained in the reservoir 42 so that liquid adhesive at the desired level impinges against the adjacent surface of the applicator wheel. When the wheel 31 rotates, the depressions 34 therein pick up liquid adhesive from the holder 42 and lcarry the material in the depressions past the doctor blade 48. The smooth periphery of the wheel is wiped clean of adhesive. The charges of adhesive are deposited from the depressions 34 onto the subjacent card or carton blank 7 so as to form a pattern of applied adhesive thereonA As the holder 42 becomes depleted, additional adhesive flows in from the chamber '76. As the level therein drops, the sensing device 81 energizes the grid 74 to augment the supply by melting more of the candle, which descends by gravity as it is used.

As an alternative form of mechanism for controlling the level within the reservoir 76, there may be provided, as shown in FIGURES 5 and 6, an arrangement including a float 91 designed to be buoyant on the surface 78 of the liquid adhesive. The particular level of the surface is controlled by an adjustment. The float 91 is supported on a trefoil spring leaf 92 having fastenings 93 at two of its ends securing the leaf of a bridge 94 in turn fastened on the cover 67. Jam nuts 96 on the threaded float stem provide for a level adjustment.

The extended central portion 97 of the spring leaf holds a magnetic shield 98. The shield moves vertically with the float and approaches or recedes from a reed switch 99 carried in a capsule 101 mounted within a housing 102 on the cover 67. Bar magnets 103 on either side of the reed switch establish a field that tends to hold the switch closed. When the level 78 rises and lifts the yfloat 91, the magnetic shield 98 moves to isolate the reed switch 99 from the field and permits the switch to assume its normally open position. This interrupts the supply of electricity to the grid 74. `On the other hand, when the level of the liquid 79 falls, the oat 91 descends and moves the magnetic shield 98 to expose the reeds of the reed switch 99 to the field. This causes the reeds to close, thus energizing the circuit to the melting grid 74 an-d causes a further liquefaction of the candle so that the level of the liquid adhesive in the reservoir 76 is raised.

The reservoir 7-6 is made of substantial volume, and its level therefore changes slowly. To get an accelerated effect, the reservoir is divided by a weir wall 106 so that melted adhesive'descending from the candle is initially confined to the relatively small volume immediately around the float. This affords rapid response. -Extra liquid adhesive overflows the weir and is stored for use in the remainder of the reservoir and serves as a cushion to smooth out variations in tlow and to compensate for heat lag in some of the mechanism.

If desired, the probe 81 instead of extending into the chamber 76 can be directed into the liquid in the reservoir 42. The agitation of the liquid by the wheel 31 tends to improve the temperature response of the probe 81 and thus improves the uniformity of the level control.

What is claimed is:

1. An adhesive applicator comprising a first frame, an applicator wheel rotatably mounted on said rst frame,

a second frame for holding a bath of liquid adhesive around a portion of the periphery of said wheel, means on said first frame for receiving a lbody of solid adhesive, a heating grid spanning the bottom of said receiving means for supporting said body, means on said first frame for receiving liquid adhesive from said grid, pivot means for supporting said second frame on said first frame for relative rotation about a fixed axis, and means concentric with said axis for conducting liquid adhesive from said receiving means to said holding means.

2. An adhesive applicator comprising a first frame, an applicator Wheel, a sha-ft carrying said applicator Wheel and rotatably mounted in said first frame, Wheel driving means on said shaft, a second frame, means supporting said second frame on said first frame for pivotal movement relative thereto on a fixed axis normal to the axis of said Wheel, means on said second frame for holding a bath for liquid adhesive in contact with a .portion of the periphery of said Wheel, said holding means including a doctor blade adapted to bear against the periphery of said Wheel, electrical means on said first frame and disposed around said shaft for heating said Wheel, a tube upstanding from said first frame and adapted to receive a body of solid adhesive, an electrically heated grid spanning the bottom of said tube for supporting said body therein and for melting adhesive from the bottom of said body, means on said first frame for receiving melted adhesive from said grid, means on said first frame and said second frame forming a passageway for said melted adhesive between said receiving means and said holding means, and means on said second frame and engaging said Wheel for holding said yWheel and said second frame in predetermined relation to each other.

3. A hot melt glue applicator comprising a first frame, a shaft journalled in and projecting from said first frame, a heater cage of annular form on said frame and disposed around the projecting portion of said shaft, heater elements disposed in said heater cage, a pattern wheel having a thermally conducting cylindrical rim, means lfor mounting said wheel on the projecting portion of said shaft with said rim spaced from and closely surrounding said heater cage, means defining a second frame including a reservoir having bottom and side walls terminating adjacent said pattern wheel rim, means for mounting said second frame on said first frame for rotation relative thereto about a fixed axis substantially normal to the axis of said wheel, a planar doctor blade, and means for holding said planar doctor blade on said bottom Wall with the end of said doctor blade against said pattern wheel rim.

4. A hot melt glue applicator as in claim 3 in which said reservoir and said heater elements are arranged in thermal communication through said pattern wheel rim.

5. A hot melt glue applicator as in claim 3 in which said shaft has an axis of rotation and said second frame mounting means provides rotation of said first frame about a second axis substantially normal to said axis of rotation.

6. A hot melt glue applicator as in claim 3 including side plates on said second frame engaging the side of said pattern Wheel rim of aligning said second frame with said pattern wheel.

7. A hot melt glue applicator as in claim 3 in which said means for mounting said second frame is a tube, and means for supplying said reservoir with melted glue through said tube.

References Cited UNiTED STATES PATENTS 2,014,391 9/1935 MacKenzie 118-261 2,399,688 5/1946- Metzner et al. 118-7 X 2,641,122 6/1953 Weber et al. 118-261 X 3,023,726 3/ 1962 Kamborian 118-7 X CHARLES A. WILLMUTH, Primary Examiner.

R. I. SMITH, Assistant Examiner.

Claims

1. AN ADHESIVE APPLICATOR COMPRISING A FIRST FRAME, AN APPLICTOR WHEEL ROTATABLY MOUNTED ON SAID FIRST FRAME, A SECOND FRAME FOR HOLDING A BATH OF LIQUID ADHESIVE AROUND A PORTION OF THE PERIPHERY OF SAID WHEEL, MEANS ON SAID FIRST FRAME FOR RECEIVING A BODY OF SOLID ADHESIVE, A HEATING GRID SPANNING THE BOTTOM OF SAID RECEIVING MEANS FOR SUPPORTING SAID BODY, MEANS ON SAID FRIST FRAME FOR RECEIVING LIQUID ADHESIVE FROM SAID GRID, PIVOT MEANS FOR SUPPORTING SAID SECOND FRAME ON SAID FIRST FRAME FOR RELATIVE ROTATION ABOUT A FIXED AXIS, AND MEANS CONCENTRIC WITH SAID AXIS FOR CONDUCTING LIQUID ADHESIVE FROM SAID RECEIVING MEANS TO SAID HOLDING MEANS.