| FR1481175A | 1967-05-19 | |||
| US3965856A | 1976-06-29 | |||
| US4347095A | 1982-08-31 |
| 1. | In an applicator system for applying a pattern of viscous liquid to a succession of segments of sheet material wherein a rotary vacuum drum rotatable about a drum axis and having a cylindrical surface coaxial to the drum picks up such segments on its cylindrical surface in succession at a segment pickup station and transports each such segment in turn to a segment delivery station, such system also comprising a rotating applicator rotating about an applicator axis parallel to said drum axis and having a cylindrical surface which is located so that during at. least a portion of the time the cylindrical surfaces of the drum and the applicator are tangent to one another, and wherein such applicator is formed with circumferential grooves on its cylindrical surface which are coaxial to the cylindrical surface and are spaced apart along the length of the applicator, and wherein there is a wire for each such groove which is held taut on opposite sides of the applicator with a median portion passing through its groove whereby the segments are prevented from adhering to the applicator, the improvement comprising a shape and radial crosssection for each such groove which is semicircular and the wire is lodged within such semicircular groove and substantially completely fills the groove. |
| 2. | In a labeling system comprising a rotatable, cylindrical vacuum drum adapted to pick up labels at a label pickup station, to hold each label on its cylindrical surface, and to transport each label to and release it at a label delivery station, and a rotatable glue applicator wheel having a cylindrical surface capable of applying glue to a label and located at least part of the time during operation of the vacuum drum in tangent relation to the cylindrical surface of the vacuum drum, the improvement which comprises a plurality of spaced circumferential grooves in the cylindrical surface of the glue wheel and a wire segment for each such groove anchored at its ends on opposite sides of the glue wheel and having an intermediate portion lodged within its groove, the configuration and dimensions of each such groove and wire being such that the glue wheel is free to rotate about its cylinder axis while the wire remains stationary and such that the wire substantially completely fills the segment of the groove within which it lies such that, as glue is applied to the cylindrical surface of the glue wheel only a very small amount is deposited in the groove. |
| 3. | The improvement of Claim 2 wherein each groove is semicircular in crosssection and the respective wire is round in crosssection and has a diameter such that it extends from near the base of the groove to its open face and substantially completely fills the space within the groove. |
| 4. | The system of any of Claims 1, 2 and 3 in which there is a doctor blade overlying the glue wheel in advance of the line of tangent contact of the glue wheel and the vacuum drum, such doctor blade serving to smooth the deposit of glue on the glue wheel. |
| 5. | In a labeling machine comprising a rotary vacuum drum having a drum axis and a cylindrical surface centered on the drum axis and capable, while rotating about such axis, of picking up labels on its cylindrical surface at a label pickup station, transporting each label to and releasing it at a label delivery station, said machine also comprising a rotary glue wheel rotating about a wheel axis parallel to the drum axis and having a cylindrical surface centered on said wheel axis, said wheel having a number of circumferential grooves formed in a cylindrical surface and spaced along the length of the wheel and formed in the cylindrical surface of the wheel, said drum and wheel rotating in opposite rotary directions with the wheel being in tangent relation to the drum during at least part of the time during such rotation, said drum and wheel during such tangent relation forming an entry sector in which the cylindrical surfaces approach one another and an exit sector in which their cylindrical surfaces recede from one another, the improvement which comprises a wire for each said groove anchored by a first anchor on the entry sector side of the drum and wheel and a second anchor on the exit sector side of the drum and wheel, said anchors being positioned so that the respective wire is lodged in its groove at the point of tangency of the wheel and drum and the portion of the wire in the exit sector guides a label applied to a container away from the glue wheel and toward the vacuum drum but not such as to leave unsightly marks on the labels. |
This invention relates to a machine for labeling containers.
BACKGROUND OF THE INVENTION
In the labeling of containers it is customary to supply labels to a continuously rotating cylindrical vacuum drum which receives the labels from a label feed at a label pickup station, holds the labels on its cylindrical surface by vacuum, causes each label to pass by a glue applicator which applies hot melt glue, e.g. , to the leading and trailing ends of the label; then transports each label to a label applying station at which the vacuum is released and the label is adhered to a container which is caused to spin and wrap the label about itself. Suitable machinery for doing this is shown, by way of example, in U.S. Patents Nos. 4,118,709 and 4,500,386. Typically the label feed is a continuous feed which supplies label stock from a roll thereof, severs individual labels from the stock and delivers each label to the vacuum drum, although a stack of precut labels may be used from which labels are supplied one by one.
It will be understood that articles other than containers may be used and that segments of sheet or film material other than labels may be used. Containers and labels are referred to herein as illustrative.
In such an operation, problems exist with regard to the pattern of glue as applied to the labels. It is common practice to use a glue applicator wheel which picks up glue from a glue supply and applies it to the labels on the vacuum drum. There is a tendency for the labels to adhere to the glue applicator wheel rather than continuing with the vacuum drum after glue has been applied. To prevent this it is common practice to provide wires which pass through circumferential grooves or slots in the glue wheel and which serve to prevent the labels from adhering to the glue wheel. Figure 1 illustrates such a wire design and is described below. However, this prior art design creates a problem or problems as follows: The wires (herein sometimes referred to as "separation wires") are located in grooves of rectangular cross-section (see Figure 2, described below) and to leave a considerable area and volume of void space which is filled with hot melt glue. This very often, if not always, results in a non-uniform glue pattern on the labels resulting in visible marks on the label which are objectionable.
OBJECTS OF THE INVENTION
It is an object of the invention to provide improvements on the label separation means of a glue applicator, or in general on any rotating liquid applicator for applying a pattern of viscous liquid onto a continuously moving sequence of surfaces or segments.
It is a particular object of the invention to provide improvements on glue applicators for labeling machines of the type described above, which eliminate or greatly diminish the difficulties in application of glue applications described above.
The above and other objects of the invention will be apparent from the ensuing description and the appended claims.
GENERAL DESCRIPTION OF THE INVENTION
In accordance with the invention, a glue wheel is provided as and for the purpose described above which has circumferential grooves formed in it which are semi-circular in cross-section; a wire is provided for each such groove which has a cross-section such that it substantially completely fills the groove, and the wire is held under tension within its groove such that its outer surface is substantially tangent to the projection of the cylindrical surface of the wheel. Preferably also each such wire is held within its groove under tension and in a position such that it cradles the label just after the glue has been applied. Preferably also a doctor blade or scraper is used and is placed in a position such that it is nearly tangent to the glue wheel and is located just ahead of the application of glue to the label.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a diagrammatic view of a vacuum drum and glue wheel showing how the separation wires are mounted in the prior art.
FIGURE 2 is a fragmentary view in cross-section of a glue wheel and separation wire as in Figure 1 but on a larger scale, and showing the configuration of the peripheral grooves in the glue wheel of the prior art and the relation of the separation wire to the groove.
FIGURE IA is a view similar to that of Figure 1 but showing the mounting of the separation wires in accordance with the present invention.
FIGURE 2A is a view similar to that of Figure 2 but showing the configuration of the peripheral grooves, and the separation wires in accordance with the present invention.
FIGURE 3 is a view in end elevation, partially broken away, of a vacuum drum, glue wheel and glue wheel drive of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to Figures 1 and 2 (prior art) , in Figure 1 a vacuum drum 10 and a glue applicator wheel 11 are shown in tangent contact, as they would be when the glue wheel is moved into contact with the vacuum drum by the glue applicator mechanism. A separation wire 12 is shown which is anchored at 13 and 14 whereby the wire 12 is stretched and held taut. As will be seen the wire 12 is in a straight line tangent to the vacuum drum when the glue wheel is moved to the position shown.
In Figure 2 a small area is shown in cross-section perpendicular to the axis of the glue wheel 11. The surface of the glue wheel is formed with a number of circumferential grooves 15, one of which is shown. These grooves are spaced apart axially along the surface of the glue wheel, each being rectangular in cross-section. Within each such groove is one of the separation wires 12 which, as described above, is held in tension and in a straight line between anchors 13 and 14.
As shown, each wire 11 is of substantially smaller radius than the depth and width of its groove 15 and it is held so that its outer surface is tangent to the vacuum drum 10 when the glue applicator wheel 11 is moved into operative position.
The groove 15 is shown filled with hot melt glue 16, such glue also extending over the surface of the glue wheel as shown.
These features, i.e., the straight line attitude of the separation wires 12, and the configuration of the groove 15 and the relationship of the separation wire to the groove 15, give rise to problems such as those described above. Since the separation wires 12 leave substantial voids around them,
these fill with glue. To some extent this glue is removed by small projections on a doctor blade or scraper or wiper (not shown) , such projections acting to penetrate and scour the grooves, but such action is incomplete and unsatisfactory.
Referring now to Figure IA a vacuum drum-glue wheel- separation wire assembly is shown in which the reference numerals are the same as in Figure 1 but with an added "a." As will be seen the separation wire 12a (which is one of a number of such wires spaced along the glue wheel 11a) is held taut between anchors 13a and 14a but at an angle such that the wires 12a are each held in their respective grooves 15a (see Figure 2A) not in a straight line as in Figure 1, but at an angle.
The numeral 20 identifies the tangent line which passes through the point of contact between the glue wheel 11A and the vacuum drum 10A. The separation wire 12A enters the space between the vacuum drum 10A and the glue wheel 11A at an angle of about 25° to 30° degrees to the tangent line 20 and it leaves the point of tangency between the vacuum drum 10A and the glue wheel 11A at a small angle A to the tangent line 20, e.g., 2° to 5°. The wire 12A then passes around anchor 14A and through a group (not shown) in the anchor 14A and is held under tension by a coil spring 21 and its end is fastened to a pin 22 projecting from a support post 23 fixed to the frame of the glue applicatory assembly. By moving the post in one direction or the other, the angle A is adjusted.
By this means the wire urges the label away from the glue wheel 11A and towards the vacuum drum 10A, thus preventing the label from adhering to the glue wheel. If the angle A is too great, the wire will leave unsightly marks on the label. By adjusting the magnitude of angle A, the desired
effect of separating the label from the glue wheel without leaving undesirable marks on the label is achieved.
It will be understood, of course, that the wire 12A is but one of a number of wires spaced along the vacuum wheel 11A, each being adjusted as described above.
Referring now to Figure 2A, in which the same numerals as in Figure 2 are used with the addition of "a," the grooves 15a are each semicircular in cross-section and the wires 12a are circular in cross-section and substantially completely fill the grooves 15a, having their outer surfaces tangent, or substantially tangent, to the projected periphery of the glue wheel 11a.
Also shown in Figure 2A is the pattern of glue 16a. As will be seen, the wires 12a nearly completely fill the grooves 15a, leaving very little in the way of void space to be filled with glue. As a result, and after the glue is acted on by a doctor blade 30 (see below with reference to Figure 3) , a very thin, uniform pattern of glue is left on the glue wheel just before it contacts the label.
Referring now to Figure 3, a drive gear 30 meshes with a driven gear 31 fixed to the shaft 32 of glue wheel 11a. This entire assembly, including drive gear 30, driven gear 31 and glue wheel 11a are moved into and out of operative contact, i.e., into and out of engagement of glue wheel 11a with vacuum drum 10a, by timing means well known in the art, e.g., to apply glue to the leading end and the trailing end of each label. A glue applicator 33 is also operated cyclically to apply glue to the glue wheel as needed. The timing of these operations may be accomplished by means well known in the art.
Also shown in Figure 3 is a doctor blade 40 anchored on the frame of the glue wheel 11a. The outer edge (i.e., the unsupported edge) of the doctor blade 40 is located in the 30° angle shown in Figure IA between the separation wire 12A and the tangent line 20. This 30° angle, may be larger or smaller than 30° (which is the preferred angle) but is such that the doctor blade 40 can, as shown in Figure 3, approach close to the line of tangency between the vacuum drum 10A and the glue wheel 12A. The function of the doctor blade 40 is to smooth the surface on the glue wheel and to remove excess glue.
It will therefore be apparent that a new and useful vacuum drum-glue wheel construction has been provided.
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