US 3472203 A
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Description (OCR text may contain errors)
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Attorneys United States Patent ABSTRACT OF THEDISCLOSURE In immersing articles'mounted on a vertically reciprocable platform in a liquid confined in a tank, e.g., for dipping cartons in molten wax, the platform is tilted back and forth on a horizontal axis, e.g., in one direction during descent into the pool and in the opposite direction during in the opposite direction during its ascent. The extentof rocking depends upon the nature of the article, that is, upon the shapes of the pockets and the diversity inthe inclinations of the pockets; it may be as little as to 20 in the case of rectilinear cartons without flanges, but can be several'times as great if desired, e.g., the platform can ascent, by-moving supporting cables (sprocket chains) vertically with different speeds, thereby permitting the liquid to enter hollow pockets within the articles and thereafter to drain therefrom, e.g., to enter open cartons and to drain out from the cartons.
"Iheinvention relates to a machine for immersing an article having a' hollow pocket in a pool of liquidwhich is confined in a tank to effect contact of the liquid with all parts of the article, and is particularly, but not exclusively, concerned with dipping assembled but open cartons and their lids in molten wax to apply a thin coat of wax.
" In conventional practice paper boar-d cartons are given a coating of paraffin or paraffin based wax (some waxes contain additives such as thermoplastics) by immersing the flat paper board, prior to assembling of the fiat board into a finished carton, in a pool of molten wax. This procedure often leads to cracks in the wax coating at the fold lines upon subsequently folding the cartons, eg at the exterior edges and corners of the cartons. These cracks in the wax can cause-premature failure of the carton.
" When an assemble-d'open carton having a closed bottom is immersed in a pool of molten wax, it is difficult to effect uniform contact of all parts of the carton and the When the open ends or mouths of the cartons are directed downwards, there remain within the carton pockets of air which'are not reached by the wax;'and when the months are directed upwards throughoutthe dipping operation, wax cannot drain out from the cartons, causing a waste of wax and leaving excessive amounts of wax inside the cartons. It is not practicable to maintain the cartons precisely horizontal.
The instant invention is directedt'o providing apparatus for immersing objects that. contain hollow pockets, particularly open-ended cartonsthat have closed. sides and bottoms, in a liquid in a manner that all surfaces of the article are brought into contact with the liquid and re tention ofiexcess liquid within the pockets is obviated. :1 In-another aspect, the invention is directed to providing ,a mechanism for moving an article-supporting platform with a tilting motion duringwdescent into a pool of liquid and ascent from said pool, which is simple and economical.
7 Now according to one aspect of the invention, the platform which supports the articles to be immersed is rocked, eg on a substantially horizontal axis during its descent into the liquid pool and subsequent ascent from it, so that all air can escape from the 'pockets and be replace-d by the liquid when the articles assume one inclination, and the liquid can drain from the pockets and be replaced by air after withdrawal from the pool.
In a specific but preferred embodiment, the rocking motion includes only two continuous motions, that is, the
platform is tilted in one direction during its descent and I be swung through or more.
According to another aspect of the invention, to which the above-mentioned broad aspect is not restricted, the platform is supported by at least two vertically movable supports secured to opposite sides of the platform, and these supports are moved with different vertical velocities, both up and down, so that the inclination of the platform is continuously changed first in one and then in the other direction during a round trip of the platform. In a specific embodiment, each said support means comprises two flexible tension members, herein for convenience called cables although suitably embodied by sprocket chains, which are secured to the platform at spaced points, and the several cables are moved by drive pulleys the peripheries of which move at different speeds. In one specific arrangement, all pulleys rotate at the same angular speed but those carrying cables secured to one side of the platform are larger in diameter than those secured to the other side of the platform.
The inclination of the platform along a direction normal to its tilting axis is selected in accordance with the manner in which the articles are mounted therein. In any case, the positioning of the articles and the said inclination are such that all articles assume at least the two following positions in succession: (l) the mouths of the pockets are directed upwards while the article is immersed in the liquid; and (2) thereafter the mouths are directed downwards while the articles are above the liquid. In the particular but simple arrangement in which the platform has a planar (preferably not continuous) supporting surface and the articles are rectilinear cartons placed thereon on their sides, with all open ends toward a common side of the platform (specifically, a side which is parallel to the tilting axis), it is convenient to mount the platform to tilt about said axis so that the said common side is higher than the opposite side when the platform is fully lowered and lower when the platform is fully raised. The tilting axis is usually horizontal but this is not essential.
The invention will be further described with reference to the accompanying drawing forming a part of this specification and showing a preferred embodiment by way of illustration, wherein: l
FIGURE 1 is a perspective of a dipping machine constructed in accordance with the present invention;
FIGURE 2 is a transverse section of the machine taken on a vertical plane;
FIGURE 3 is a perspective of a load of cartons when on the platform and above the pool of liquid, parts of the elevating and tilting mechanism being shown and the platform appearing in phantom; and
FIGURE 4 is a perspective of the load of cartons when immersed in the pool of liquid, parts of the tank and platform appearing in phantom.
The machine includes a tank 5 which is open at the top and contains heating pipes 6 for maintaining a pool of liquid wax in molten condition. Standards 7 are secured to the tank and extend upwards therefrom, being interconnected by pairs of transverse and longitudinal stringers 8 and 9, respectively. The standards include vertical corner plates 10 and transverse horizontal shafts 11 and 12 are mounted in these plates, e.g., by suitable anti-friction bearings, not shown. The shaft 11 carries, keyed or otherwise fixed thereto for rotation therewith, drive pulleys 13, 13', 14 and 14'. The shaft 12 carries a pair of idler pulleys 15 and 16. The shaft 11 is driven by a sprocket wheel 17 and chain or belt 18 from an electricmotor 19 which is supported from the standard by a platform 20. In this embodiment, all six pulleys 1316 are sprocket wheels. The sprockets 13 and 13 are alike,
as are the sprockets 14 and 14, and the former have diameters greater than the latter, whereby their peripheries move faster than those of the latter when all rotate at the angular speed of the shaft 11. Similarly, the sprocket 15 is, in this illustrative embodiment, larger than the sprocket 16, although this is not essential when these sprockets are independently rotatable.
The platform 21 shown in FIGURES 1 and 2, is in this embodiment a wire cage having a flat bottom, four sides 22 and a hinged lid 23. While other forms of platform are suitable, a cage allows the flow of wax to and from the cartons, and lid 23 will resist buoyancy of the cartons. The platform is suspended by four sprocket chains 24, 25, 26 and 27. The chains 24 and 25 jointly constitute one vertically movable support and, they are attached at spaced points to one side of the platform and run over the large drive sprockets 13 and 13', respectively, the chain 25 passing additionally about the idler sprocket 15. The chains 26 and 27 jointly constitute another vertically movable support, are attached to the other side of the platform, and run over the small drive sprockets 14 and 14', respectively, the chain 27 passing additionally about the idler sprocket 16. The ends of the chains 24 and 25 are both connected to a weight 28, and the ends of the chains 26 and 27 are both connected to another weight 29. The weights can move vertically to counterbalance the weight of the platform, and may be guided by lugs 30 which are slidable along vertical rods 31 fixed to the standards 7. The lengths of the chains from the platform to the drive pulleys are such that when the platform is in its uppermost position, as shown in FIGURES 1 and 2 the side of the platform at which the chains 24 and 25 are attached, is higher than the platform side at which the other two chains are attached; and, the diameters of the sprockets on the shaft 11 are so related that, when this shaft is rotated and the platform moved to its lowermost position, the first-mentioned side of the platform is lowered more rapidly than the other side. In the lowermost position, the inclination of the platform is reversed, as shown by the chain lines in FIGURE 2.
Limit switches 32 and 33 are mounted on one of the longitudinal stringers 9, as is shown in FIGURE 1. These switches have feeler arms that are engaged by an abutment 34 carried by the chain 25. These switches are connected to an electrical circuit for the motor 19 in a manner not shown in detail but obvious to those skilled in the art to perform the following functions: When the platform is in its uppermost position, the motor 19 is started manually to turn the shaft 11 in a direction to pay out the chains. When the platform has reached its lowermost position, in which it is fully immersed in the pool of liquid within the tank 5, the abutment 34 strikes the limit switch 32. This reverses the motor to move the platform upwards. (Alternatively, it may merely shut off the motor to afford a soak time, and the ascent can be begun manually, or automatically by a time-delay device.) When the platform has again been raised, the abutment 34 strikes the limit switch 33 to stop .the motor.
Operation of the device will be described with reference to FIGURES 3 and 4, as applied to coating cartons 35 and carton lids 36 with wax. To this purpose, the articles 35 and 36 are placed within the raised cage platform 21 so that the open ends or months of all articles are directed downwards, towards the lower side of the platform and the lid 23 is shut to prevent shifting of the articles.
Loading can be effected by a conveyor mechanism, if
desired employing an auxiliary cage, not shown because not a part of this invention. The motor 19 is then started,
and the sprockets 13, 13', 14, 14 pay out the chains to lower the platform until the articles are fully immersed in .the liquid wax within the tank 5. Upon reaching the lowermost position, the platform is tilted as appears in FIGURE 4, with the. mouths of the cartons 35 andlids 36 directed slightly upwards. Air initially present within these articles readily escapesand all surfaces of the article are brought into contact with the wax. When the platform is raised by reversing the motor 19, the cartons and lids are again tilted to their original position, shown in FIG- URE 3, permitting the liquid Wax to drain from the interiors into the liquid pool.
It is evident that it is desirable to have the inclination of the articles relative to the horizontal somewhat greater in the raised position than in the lower position, because drainage of the wax occurs more slowly than the escape of the gas. This is shown in FIGURE 2, in which the platform is inclined about 11 to the horizontal when in its uppermost position but only about 6 to the horizontal when in its lowermost position.
1. In apparatus for dipping articles in a liquid, which comprises a tank for holding a pool of said liquid, 'a reciprocable platform for holding said articles and adapted to be lowered into and raised from said pool, means for moving said platform up and down, the improvement of means for rocking said platform during the up and down movements thereof to vary the inclination of said articles during their movement, said means for moving the platform comprises at least first and second pairs of pulleys, the pulleys of each pair having equal diameters but unequal with respect to the other pair, first and second cables secured respectively to opposite sides of the platform and extending respectively about a separate one of said pairs of pulleys, reversible drive means for driving said pulleys at equal angular speeds whereby to drive said cables for effecting said rocking movement of the platform by moving one of said sides more rapidly in the vertical direction than the other side.
2. Apparatus as defined in claim 1 wherein said pulleys are sprockets and said cables are sprocket chains.
3. Apparatus as defined in claim 1 wherein said platform is formed of wire mesh and has sides extending upwards from therefrom for retaining the articles thereon.
4. Apparatus as defined in claim 1 wherein each cable comprises two line-elements, said elements secured at spaced points on said platform and each element extending over a drive pulley.
5. Apparatus as defined in claim 4 wherein said means for the platform includes at least two large-diameter and two small-diameter pulleys fixed on a common shaft for rotation at a common angular speed, and wherein the two line elements from one side of the platform extend over large-diameter pulleys and those from the other side extend over small-diameter pulleys.
References Cited UNITED STATES PATENTS 198,383 12/1877 OHanlon 254144 X 561,712 6/1896 Lynch 134-'160X 657,354 9/1900 Muller 134 X 681,275 8/1901 Stiefel et al 134-160 X 740,811 10/ 1903 Costello 11830 X 851,236 4/1907 Hartog 118-30 2,643,662 6/1953 Bunce 134164 2,953,969 9/1960 Pepple' 254144 X 3,047,436 7/1962 Zinty 134-160 X 3,320,963 5/1967 Walker 134160 X 3,367,302 2/1968 Schloder et a1. 118-30 FOREIGN PATENTS 9 1,161,741 1/1964 Germany.
500,270 11/1964 Italy.
MORRIS KAPLAN, Primary Examiner US. or. YX.R. 134M160; 254-144