|Publication number||US3642181 A|
|Publication date||Feb 15, 1972|
|Filing date||Jun 5, 1969|
|Priority date||Jun 5, 1969|
|Publication number||US 3642181 A, US 3642181A, US-A-3642181, US3642181 A, US3642181A|
|Inventors||Steffens David G, Thomas Buford L|
|Original Assignee||Valco Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (15), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Thomas et al.
[4 Feb. 15,1972
 VERTICAL ADHESIVE APPLICATOR HEAD  Inventors; Buford L. Thomas; David G. Stetfens, both of Cincinnati, Ohio  Assignee: Valco, lnc.-, Cincinnati, Ohio  Filed: June 5, 1969 211 Appl. No.: 830,692
 U.S.Cl ..222/517, 222/558, 118/410, 401/264  Int. Cl. ..B05c UB6  Field ofSearch ..222/517, 556,558; 118/410, 118/411; 401/264  References Cited UNITED STATES PATENTS 992,885 5/1911 Lautenschlager ..401/264 1,701,949 2/1929 Davenport..... ...222/558 X 2,491,185 12/1949 Kambon'an ..118/411 3,126,574 3/1964 Fox ..118/411X 3,299,854 1/1967 Van Lobensels ..118/411 FOREIGN PATENTS OR APPLICATIONS 462,308 3/1951 Italy ..222/556 Primary ExaminerRobert B. Reeves Assistant Examiner-Frederick R. Handren AttorneyMelville, Strasser, Foster & Hoffman ABS IRACT An adhesive shutofi valve mechanism for the head of an adhesive applicator comprising in part a shuttle assembly spaced a fractional distance from the outlets in said head through which the adhesive is applied to an adjacent surface, said fractional distance being such as to fonn and maintain a puddle of adhesive around said outlets to prevent the admission of air thereto until said valve mechanism is activated, and an internally pivoted member adapted to align one or more passageways with said one or more outlets during the operative periods of applying said adhesive.
7 Claims, 5 Drawing Figures PATENTEDFEB 15 I972 "3,642,181
INVENTOR/S Bum/2D L. E MAS DA Wu G. STEFFE/VS BACKGROUND OF THE INVENTION This invention relates to the field of devices known as adhesive applicators, which applicators are used to apply a viscous glue to flat surfaces such as carton flaps for packing or shipping containers. More specifically, the invention includes an applicator which utilizes an external valve mechanism to control the drying out of the outlets, a problem of the prior art applicators.
The typical applicator includes an adhesive source, applicator head, and means to transmit the rather viscous substance from the source to the head. The head is provided with a reservoir chamber, and a series of ports or vanes communicating therewith through which the adhesive is applied. Preventing the glue from drying out in the vanes has been a major problem for the industry.
There have been two general approaches to solving this problem, the first being the use of an internal shutoff valve in the applicator head. The other approach has been with the use of external wetted felt pads. For a more detailed consideration of the use of pads, and their related problems, reference is hereby made to the assignees copending application, Ser. No. 724,202, now U.S. Pat. No. 3,517,646, for Improvement In Adhesive Application Apparatus. While said copending case was an improvement over the wetted felt pads, the present invention represents a different concept in providing unique internal and/or external means for assuring the flow of adhesive only at the designated time. In brief, with each approach the prior art sought means to prevent air from reaching the glue and thus minimiie any drying thereof. However, for one reason or another it was a difficult problem to overcome. The instant inventions different concept is based upon the access of the air to the glue by means which control the drying of the glue about the vanes.
SUMMARY OF THE INVENTION To accomplish the desired objectives, this invention contemplates an adhesive applicator having a pivotal member spaced a fractional distance from the respective ends of the outlet vanes of the applicator head. The above-mentioned spacing is directly related, for reasons to be discussed hereinafter, to the viscosity of the adhesive. The types of adhesive or glue with which this invention is concerned are the classes of glues known as dextrines, resins, and latexes which have a viscosity in the range of 3002,000'centipoises. With materials of this type, the spacing between the external member and the applicator head will be between about 0.001-0.007 inch.
The alternative or supplemental adhesive shutoff member is an elongated insert movable with respect to the internal ends of the outlet vanes. The spacing therein is more limited such that it falls within the range of 00015-00020 inch.
The former spacing is designed so as to maintain a puddle of glue on the surface of the applicator head, and the adjacent surface of the shuttle assembly during periods of extended inactivity such as a shutdown. This puddle allows a skim of glue to dry on the outer edges, thus preventing further drying. After allowing the applicator head to stand until the outside glue is thoroughly dry, the gluing operation may be efficiently and effectively resumed by the movement of the shuttle assembly. This movement breaks the dry glue around the edges and the vanes are completely open and usable.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of an adhesive applicator constructed according to the teachings of this invention.
FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, showing the applicator in the inoperative position, i.e., no adhesive being applied.
FIG. 3 is a sectional view similar to FIG. 2 but showing the applicator in the operative position.
FIG. 4 is a sectional view similar to FIG. 2 but showing a modification thereof.
FIG. 5 is a sectional view similar to FIG. 3 but showing the modification of the applicator in the inoperative position.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Considering the invention in more detail, it will be observed from FIG. 1 that the adhesive applicator 10 comprises a head 12, a conduit 14 leading thereto, and a shuttle assembly 16 adjacent end 18 ofthe head 12.
The initial elements, i.e., head 12 and the conduit 14, are known per se and hence form no limitation on this invention. Nevertheless, for convenience FIG. 2 is presented to illustrate the inner construction whereby the glue is caused to pass through the conduit 14 into the head 12 where it enters chamber 20. This chamber is perpendicular to the conduit 14 and traverses essentially the full width of the head 12. From chamber 20 a series of outlets 22 are provided to release the glue in the chamber to the underlying surface receiving the glue.
The end 18 is semicircular in configuration with a radius equal to one-half the thickness of the head 12. In operation the base of the head 12 rides the surface to which the glue is applied while the outlets 22 are disposed in a generally vertical position.
When the applicator 10 is not applying glue, the shuttle assembly 16 is an effective means for protecting the outlets 22 from drying out. Without such a mechanism one or more of the outlets could become clogged resulting in a poor adhesive pattern. In any event, this assembly in its most preferred embodiment is composed of a curved transverse member 24, and
, two arms 26, 28, pivotally mounted to head 12 by pins 30. By
securing the assembly 16 in this manner it may be readily moved to effect the gluing operation.
It will be observed in the sectional views that the inner surface 32 of transverse member 24 is curved essentially along the same radius as end 18. By positioning the pins 30 at the center of said radius, the transverse member 24 can be pivoted thereabout and a substantially constant difference or spacing 34 can be maintained between the surface 32 and 18. The difference for the present invention, when using adhesives having a viscosity of 3002,000 centipoises, is in the range of 0.001-0.007 inch. The reasons for this critical range will be explained presently.
The present invention is unique over the prior art in that controlled drying of the glue is permitted about the outlets. Experience has indicated that if the spacing is less than about 0.001 inch, an insufficient skim of dried glue is formed. That is, the glue will dry and crack thereby exposing the outlets and permitting air to get into them. With a spacing in excess of 0.007 inch, the glue will not hold and will run off resulting in an ineffective puddle of glue. It should thus be apparent that the spacing 34 between surface 32 and end 18 is critical. However, it should also be recognized that the spacing 34 is dictated by the viscosity of the adhesive. That is, with more or less viscous glues the spacing range may be shifted. But for the aforementioned class of glues, the range of 0.001-0.007 inch will suffice.
The types of glue which fall within this class are the dextrine, resin, and latex adhesives. A specific example is J- 3135 [viscosity 1,500 centipoises], a resinous adhesive manufactured by H. B. Fuller Company. For such an adhesive, a spacing of about 0.005 inch is adequate.
After operation, the assembly 16 is positioned in the manner shown in FIG. 2. At this stage the controlled drying occurs. To activate the system member 24 is rotated upwardly to the position shown in FIG. 3 thereby cracking the dried glue and exposing the outlets 22 which are now clear and usable.
To return the transverse member 24 to the inoperative position, means have been provided to effect this automatically. While many different methods are possible to effect this movement, one relatively simple method is shown in FIG. 1. Specifically, reference is made to coiled spring 36 shown attached to the pin 30. In order to prevent the shuttle assembly from continuing beyond the plane of the applicator head, stop 38 is provided. Thus, the arm 28 is shown extended so that it will be engaged by the stop 38 at the proper position.
The embodiments illustrated in FIGS. 4 and 5 represent a modification to the one discussed above. The latter embodiment is particularly adaptable to vertical systems wherein the article receiving the glue is moving in a vertical path. One of the problems encountered in the vertical glue applicators is the problem of drippage. This is caused by the fact that the lateral which feeds the glue to the small vanes or outlets for application onto the desired surface is, in fact, a hydraulic head of glue. Attempts have been made to minimize this problem by utilizing longer vanes and/or drilling the vanes down on an angle. The improvement illustrated in the latter FIGURES includes an internal valve in the applicator head 12 between the lateral feed channel 20a and the vanes 22.
The internal adhesive shutoff action is accomplished by means such as an elongated member 40 disposed in the chamber 20, which member has been provided with a series of through passageways 42 for alignment between the chamber 20a and the outlets 22. However, it should be understood that other means, such as a milled slot may be utilized to pass the adhesive between the chamber 20a and the outlets. In either case, during the operative periods, such as illustrated in FIG. 4, the one or more passageways 42 are merely extensions of the outlets. During the inoperative period there is a misalignment which effectively shuts off any flow of the glue between the chamber 20a and the outlets 22. With the valving mechanism in the inoperative position, placing the head 12 vertically will not allow the hydraulic head of glue in the chamber 20a to drip out of the outlets. The extremely small amount of glue remaining in the outlets will not drip since there is no head" on it. To effect the adhesive or glue shutoff, the tolerances between said internal member 40 and the wall of said chamber 20 should be controlled within the range of 0.00l5-0.0020 inch. A further optional, but desirable feature for meeting tolerance requirements is the provision of a metallic tubular insert contiguous with the walls of chamber 20.
The movement of the valving mechanism may be tied directly to the shuttle assembly so as to achieve the dual control on the flow of adhesive, or they may be rendered independently operative by means known in the art. While the movement thereof has been illustrated in a relatively simple way above, it should be understood that other means are contemplated. For example, motorized or pressurized devices such as an air cylinder may be employed for the purpose.
While the combination shutoff means has particular utility in vertically operated applicator heads, it has been found that as a practical matter, the internal valve member 40 is more effective in reducing intermittent dripping, a major problem with vertical systems. On the other hand, the shuttle assembly 16 is more effective in eliminating prolonged dripping such as would occur after a shutdown following a production run.
In view of the modifications which have been noted above, and the ones which may become apparent to those skilled in the art upon reading these specifications, no limitatio'n is in tended to be imposed herein except as set forth in the appended claims.
1. In an adhesive applicator having an applicator head for applying adhesive to one or more outlets to a surface moving relative thereto, whereby said applicator is applying an adhesive whose viscosity falls within the range of 300-2,000 centipoises, the improvement comprising in combination therewith, a shuttle assembly spaced a distance within the range of 0.00l0.007 inch from the external end of said out lets and adapted to substantially terminate the flow of adhesive therethrough, whereby during the operative periods of applying said adhesive said member is positioned at a first location relative to said outlets, and during the inoperative period in which no adhesive is being applied the said member is pivoted an angular distance to a second location, the latter location being such as to close off said outlets to the flow of adhesive.
2. The adhesive applicator as claimed in claim 1, wherein said applicator head at the said outlet end is configured so as to provide a curved surface of predetermined radius, and said shuttle assembly adjacent said outlets is provided with a concave surface having substantially the same predetermined radius, such that in moving said assembly from the operative to the inoperative position the respective surfaces will be maintained from one another by a distance within the range of 0.001-0.007 inch.
3. The adhesive applicator as claimed in claim 1, including means for pivotally mounting said shuttle assembly to the exterior of said applicator head.
4. The adhesive applicator as claimed in claim 3 including means for automatically returning said assembly from the operative position to the inoperative position.
5. The adhesive applicator as claimed in claim 4 wherein said last named means is a spring 6. The adhesive applicator as claimed in claim 1, wherein said applicator head is provided with an elongated chamber communicating with said outlets, and wherein said shuttle as sembly includes an elongated insert within said chamber and adapted to align one or more passageways therein with said one or more outlets during the operative periods of applying said adhesive.
7. The adhesive applicator as claimed in claim 6 including a second chamber parallel to and communicating with said elongated chamberl
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|U.S. Classification||222/517, 222/558, 118/410, 401/264|