US 2991609 A
Description (OCR text may contain errors)
July 11, 1961 R s. RANDALL VACUUM BAG SEALING MACHINE 2 Sheets-Sheet 1 Filed March 4, 1957 Ray/25%;? BY
R. s. RANDALL VACUUM BAG SEALING MACHINE July 11, 1961 2 Sheets-Sheet 2 Filed March 4, 1957 MWETU/P Unite States Patent 2,991,609 VACUUM 'BAG SEALING MACHINE Ralph S. Randall, 3380 20th 'St., 'San Francisco, Calif. Filed Mar. 4, 1957, Ser. No. 643,684 2 Claims. (Cl. 5337 1) The present invention relates to improvements in a vacuum bag sealing machine, and its principal object is to provide certain improvements in machines similar to those described in my co-pending applications, Serial Numbers 486,797, now Patent No. 2,844,925; 521,176; and 550,921, now Patent No. 2,870,591.
Machines of this type usually consist of a plafiorm adapted to have a series of open-ended bags positioned thereon, a hollow housing hinged thereto and adapted to be lowered upon the platform so as to form a chamber therewith, means for evacuating the chamber so as to pull the air out of the bags, possible means for re-filling the bags with an inert gas, and sealing elements operable to descend upon the ,open ends of the bags for heat-sealing the same.
, The present invention is directed principally to the positioning of the bags on the platform prior to the evacu ating process in such a manner that it'may be carried out with a minimum of hand labor and at a great saving of time.
In this connection it is proposed to limit the amount of labor necessary to the mere placing of the bags in marked positions and to cause the descending cover to press or anchor the open end of the bag upon the platform.
It is further proposed to cause the cover or housing to merely anchor opposing edges of the bags upon the platform so as to leave the major portion of each bag open for evacuation of air from each bag and re-introduction of an inert gas.
It is further proposed to provide certain improvements in the feeding of the inert gas in such a manner that the gas is fed in the form of jets directed toward the open ends of the bags substantially in the plane thereof, whereby the gas sweeping over the open end of eachbag produces a lifting effect on the upper sheet of the bag and tends to further open the bag for free admission of the gas thereinto.
It is additionally proposed to cause the heat sealing member to descend upon the open ends of the bags after the bags have been filled with inert gas, and to cause the descending heat element, prior to its sealing engagement with the bag, to act on one of the bag anchoring means for pulling the end edge of the bag engaged thereby endwise for stretching the open end of the bag to present perfectly flat surfaces to the sealing element before the latter becomes active.
Further objects and advantages of my improved vacuum bag sealing machine will appear as the specification proceeds, and the new and useful features of this invention will be fully defined in the claims attached hereto.
The preferred form of my invention is illustrated in the accompanying drawings, forming part of this application, in which:
FIGURE 1 shows a perspective view of myv-acuutn bag sealing machine;
FIGURE 2, a plan view, on an enlarged scale, of the machine in fully open position;
FIGURE 3, a cross-section taken along line 3-3 of FIGURE 2;
FIGURE 4, a cross-section taken along line 4--4 of FIGURE 2;
FIGURE 5, an enlarged detail view of the anchoring means for the end edges of the bag; and
FIGURE 6, a section taken along line 6--6 of FIG- URE 5.
While I have shown only the preferred form of my invention, I wish to have it understood that various changes or modifications may be made within the scope of the claims hereto attached, without departing from the spirit of the invention.
Referring to the drawings in detail, my vacuum bag sealing machine 1 is mounted on a rectangular box 2 which may be thirty-two inches long and eleven inches wide, and which presents a perfectly flat top platform 3.
The box may be supported on atable or the like to bring the platform up to a convenient height for an operator to place bags thereon in a predetermined order, the bags having been previously filled with suitable merchandise, such as sliced ham, cheese, sausage or the like and having open ends. The machine here shown and described is constructed to hold four bags at a time.
Mounted along the forward edge of the platform and spaced therefrom sufficiently for accommodating other elements to be described, is a metal strip 4 which has four relatively short, thin rubber markers 5 thereon in spaced relation, each marker having a white dot 6 near its right end, as viewed from in front.
The markers 5 areprincipally intended to facilitate thepro-per placing 'of the bags by the operator who positions the four bags in parallelrelation, with the right edge of each bag resting on a marker and the open end of the bag projecting forwardly and over a second strip 7 arranged forwardly of the first strip.
The second strip is slightly wider than the first strip and is made ofrelatively soft rubber material, and serves as an anvilfor the descending heating element.
The placing of the four bags on the platform in the manner described'is all that is requiredin the way of manual operation by the operator.
Forwardly' of the strip 7 there is mounted an inverted,
' substantially semi-circular channel 8 which is connected,
throughbottom openings in the platform, with the gas lines 9' connecting with a source of inert gas under pressure. "The channel 8 is formed with aseries of relatively small holes '10 right opposite the open ends of the positioned bags, so that the jets of gas streaming toward the open ends of each bag have a tendency to lift the upper sheets through suction applied to the upper face of said upper sheet. The channel is slightly spaced forwardly of the rubber strip, as shown.
A hollow cover or housing '11 is hinged to the box having the platform, by means of brackets 12 and 13, operating on a horizontal shaft 14, so that the housing may be swung upon the platform. The housing has a 15 projecting beyond the platform, when the housing is lowered and has an all around gasket 16 adapted to come to rest on the extreme rim of the platform, so that the housing forms a sealed chamber with the 'plat' form. a
The housing has four cylinders 17 rising therefrom in alined relation and near the forward edge thereof, the cylinders being disposed over the four sealing zones. Each cylinder is divided, by means of a horizontal diaphragm 18 into an upper compartment 19 and a lower compartment 20 in communication with the main sealing chamber, as at 21.
Each upper compartment connects, through a nipple 22 with a conduit connected with a source of pressure (not shown) and controlled by a solenoid valve (not shown).
Each diaphragm is normally forced upward by spring 25 in the form of a bar, extending lengthwise through the full length of the housing. This heating element is located with respect to the front edge of the housing so that it registers with the rubber strip 7 of the platform when the housing is lowered upon the latter.
The housing also has a metal bar 26 descending from the upper wall thereof, this bar being spaced from and parallel to the heating bar 25. Bar 26 is locatedwith respect to the lower platform to remain substantially rearward of the strip 4 when the housing is lowered, but to; bring the anchoring elements carried by its front face immediately over the strip 4 and into registry therewith. There are four sets of anchoring elements, one lfOl. each bag, and one of them is shown in detail in FIGURES and 6.
One of the anchoring elements is in the form of a brace 27 pivoted upon the front face of the bar 26, as at 28, and made to lean sidewise, that is, to the right as viewed fromjin front, by a pin 29 projecting from the plate, with a spring 30 serving to urge the brace upon the pin 29.
The brace terminates, at its lower end, in a shoe 31, which is secured to the brace by the pin 32, so as to allow of a slight amount of pivotal motion of the shoe with respect to the brace. The shoe projects downwardly beyond the bottom edge of the bar 26, and is positioned to bring the shoe directly over the rubber marker 5 of the metal strip 4 when the housing descends upon the platform.
. When, as the brace descends upon the marker, with the right edge of a bag interposed, the shoe will first right itself on the pin 32 to a position parallel to the marker. Next, the brace will swing on the pivot 28, against the spring 30 to lose contact with the pin 2Q. The right edge of the bag is now firmly anchored with respect to the marker Son the strip 4.
It will be noted that in this position, the brace is still capable of a certain amount of swinging motion toward the pin 29, so that, when a pull to the left is exercised on the open end of the bag, the brace, in attempting to swing to the left, will deepen the engagement of the shoe with the bag and will firmly clamp'the shoe upon the bag and the latter upon the marker. 7
At the same time that the shoe clamps upon the right edge of the bag, the roller 33 clamps upon the left edge of the bag. This roller is revolvably mounted upon the front face of the bar 26 by means of a pin 64 in such a manner that its bottom portion is substantially on a level with the bottom edge of the bar, and has an annular series of reversely bent rubber teeth 35 arranged thereon. The teeth are dimensioned to bring the extremity of the lowermost tooth slightly below the bottom of the shoe.
Thus, as the shoe descends upon the right edge of the bag, the lowermost rubber teeth descend upon the left edge. of the bag and firmly clamp the latter edge upon the metal strip 4, the roller and the brace being spaced to correspond substantially to the spacing between the right and left edegs of the bag,
The two end edges of the bagare now firmly clamped uponthe strip 4, but the intermediate position of the bag isstillloosely resting. on the strip, ready to be opened for the withdrawal of the air from the bag by suction and the re-charging of the bag with an inert gas from the inverted channel 8 in themanner previously described.
After the bag has been charged with inert gas or vacuurnized, the sealing element 25 is made to descend upon the rubber strip 7 disposed forwardly of the metal strip 4. This sealing element is operated by the diaphragm 18 in the cylinder 17 in the manner described, and while on its downward path and before striking the bag, operates the roller 33 to rotate clockwise so as to pull the left edge of the bag away from the right edge and to scratch and smoothen the, open end. of the bag.
This is. accomplished by means of a crank pin 36 projecting from the forward face of the roller and a pair of cleats 37' and, 38. projecting from the rear face of the heating element in driving relation to the crank pin. As thesealing element descends, the upper cleat 37'drives crank pin downward for turning the roller clockwise, and as the sealing element ascends, the lower cleat 38 turns the crank pin back to its original position.
Various operating controls for the machine have not been described in detail, since the invention is particularly directed to the anchoring of the bags, the manner of charging; the same with nitrogen, and the stretching and smootheningof'the bags prior to the sealing operation.
In operation, with the machine in open position:
(1) The operator places the four bags, which have been previously filled, upon the platform, with their open ends facing forward and overlying the metal strip 4 and the rubber strip 7 and their right edges overlying the markers 5 and in line with the white dots 6.
(2) The operator then pushes a switch button which causes the hollow housing to descend upon the platform to form a vacuum chamber therewith.
(3) As the housing descends, the shoe 31 of the brace 27 and the lowermost tooth of the roller 33 descend upon opposite edges of the open bag, and clamp the said edges upon the strip 4. During this operation the shoe 31 rights itself with respect to the upper face of the strip 4 and the brace 27 swings away from the pin to provide a slight clearance. The intermediate portion of the bag remains open, the degree of opening depending upon the bulk of the product within the bag.
(4) Release of the manually operated switch starts evacuation of the chamber.
(5) As the vacuum reaches a desired degree, nitrogen is admitted to the chamber through the channel or tube 8 and theperforations 10 in the form of jets. These jets, in case the two sheets of the bag are too close to present an opening, will pass over the upper surface of the upper sheet and produce enough suction on the upper sheet to lift the same and open the bag. This is very important, since, if the nitrogen is fed from any other point of the chamber, there is a tendency for the nitrogen to close the bag and to keep the nitrogen out of the bag.
(6) When the desired nitrogen pressure, still less than atmospheric, has been reached, the pressure operates a valve admitting nitrogen or air at atmospheric pressure to the upper side of the diaphragm 18.
(7) The diaphragm pushes the sealing element 25 downward.
(8) The upper cleats 37 of the heating element bear down on the crank pins 36 of the rollers 33, causing the rollers to turn clockwise. The teeth on the rollers pull the left edges of the bags toward the left, that is, away from the shoes 31, thereby tightening the hold of the shoes, and smoothing out the open ends of the bags.
(9) The sealing element descends upon the open ends of the bags, over the rubber strip 7, and heat seals the bags.
(10) After a predetermined time allowed for the sealing operation, the chamber is vented to the atmosphere, the cover is raised and a vacuum is applied to the upper face of the diaphragm to cause the heater bar to return toits initial position.
(.111) As the heater bar ascends, the lower cleats 38 act on the crank pinsv 36 for turning the rollers 33 anticlockwise and back to their original position.
1. In a bag sealing machine, a platform adapted to receive an open-ended bag thereon in a predetermined position, a cover movable upon the platform in a predetermined path to form a chamber therewith and a pair of clamping members carried by the cover for clamping opposing edges of the bag end upon the platform as the cover moves upon the latter, one of the members. being an inclined brace operable for tightening the clamping f gement when pull is exerted on the opposite. edge of the bag, and the other member being a roller adapted to exert such pull when rotated.
Z- 1 1 a b ealing machine, a platform adapted to receive an open-ended bag thereon in a predetermined position, a cover movable upon the platform in a predetermined path to form a chamber therewith, and a pair of clamping members carried by the cover for clamping opposing edges of the bag end upon the platform as the cover moves upon the latter, one of the members being an inclined br-ace operable for tightening the clamping engagement when pull is exerted on the opposite edges of the bag, and the other member being a roller adapted to exert such pull when rotated, with means carried by the cover for rotating said roller after the clamping engagements have been efiected.
References Cited in the file of this patent UNITED STATES PATENTS Thompson Aug. 29, 1939 King June 26, 1951 Bartelt Aug. 25, 1953 Prohaska Jan. 10, 1956 Feinstein Jan. 31, 1956 Lorenz et a1 June 12, 1956 Mahafiy et a1 Ian. 22, 1957 Fogwell et a1 May 13, 1958 Mahaify et a1. Nov. 4, 195-8