US2888792A - Vacuum sealing machine - Google Patents

Description

June 2, 1959 R. 3. JAMES VACUUM SEALING MACHINE Filed Sept. 13, 1956 3 Sheets-Sheet l INVENTOR ROBERT C. L/IMES ATTL )RNEYS June 2, 1959 I R. c. JAMES 2,888,792

VACUUM SEALING MACHINE Filed Sept. 13, 1956 s Sheets-Sheet 2 v INVEIQTOR $05.52;" C. J

HMES BY @4/\/ ATTORNEY June 2, 1959 R. c. JAMES 2,838,792

VACUUM SEALING MACHINE 7 Filed Sept. 15, 1956 3 Sheets-Sheet s I 45 3o 1 M8 h 7 o T fioazer C. JAIME;

ited States Patent VACUUM SEALING MACHINE Robert C. James, Pointe Claire, Quebec, Canada, as-

signor to Griswold Engineering Limited, Montreal, Quebec, Canada, a corporation of Canada Application September 13, 1956, Serial No. 609,748

9 Claims. (Cl. 53-=-112) The present invention relates to apparatus for the leakproof sealing of bags or envelopes of heat-sealable plastic material.

The use of plastic material bags in which meats or like food products are packed and heat-sealed under vacuum is Well established at the present time. 7

While there are many and varied types of apparatus available for the purpose of evacuating the air from the bags and heat-sealing the mouths of the bags, a problem still exists with respect to the maintaining of a satisfactory air-tight seal. In order to establish a satisfactory the margins directly in advance of the fluid conducting member to complete the seal.

This method is carried out in a preferred form of apparatus by the use of a pair of opposed jaws at least one of which is provided with heating means. One of these jaws is fixed and the other one movable and they seal on a bag of this nature, which, as mentioned above,

is'usually made from plastic material and is sealed by the application of heat and pressure, it is necessary that theportion of the bag to be sealed be maintained in a flat-and unwrinkled condition.

Normally, and in the prior art arrangements known,

especially ifa relatively bulky product is being wrapped,

which makes it difiicult to establish the complete face to face contact for the air-tight seal required. With this in mind, various mechanical expedients have been proposed to stretch and maintain the mouth of the bag in stretched condition during the air exhausting operation 7 and subsequent sealing. For example, air evacuation nozzles have been proposed having a width equal to the entire width of the bag. Resiliently spaced apart-nozzles adapted to keep the mouth of the bag stretched flat have also been proposed to overcome the condition mentioned above. Some of these prior art arrangements utilize two complete sets-of jaws, one to retain the bag for the air exhaustion, and the other to perform the heat-sealing operation. :However, since all of these arrangements still perform the air exhausting operation prior to the heat-sealing, and in some cases are suitable only for one size of bag, they are not completely satisfactory In accordance with the present invention, amajor portion of the heat-sealing is accomplished with the bag in are faced with heat resistant resilient material so that they can operate in combination with an air evacuation nozzle which extends between the jaws into the interior of the bag to be sealed. Due to the resilient material of the jaw facings a vacuum-proof seal is established between the bag and nozzle and the bag is first heat-sealed under pressure with the exception of the relatively small area surrounding the nozzle.

Automatic means are provided in the preferred apparatus according to the invention whereby the air is exhausted from the bag, the heat-seal completed, and the air evacuation nozzle withdrawn; all of these operations being performed automatically and in time related sequence.

More specifically, an auxiliary sealing unit or jaw mounted on one of the main opposed jaws acts tov seal the unsealed portion of the bag directly in front of the air exhausting nozzle so as to complete the seal while the interior of the bag is still under vacuum pressure and the nozzle is automatically withdrawn to a position clearing the auxiliary jaw substantially simultaneously wi the completion of the seal.

It will be understood that while the present disclosur and drawings refer specifically to the use of a single nozzle for the purpose of exhausting air from the interior of a plastic bag, more than one nozzle might be used and a fluid or powder might be introduced into the bag simultaneously with the air exhausting operation.

Having thus generally described the nature of the invention, particular reference will be made to the accompanying drawings, wherein there is shown by Way of illustration a preferred embodiment of a vacuum sealing apparatus in accordance with the invention, and in which:

Figure l is a diagrammatic view in perspective elevation of a heat-sealed package as performed by the apparatus of the invention.

Figure 2 is a cross-sectional view of the package shown in Figure 1 prior to the heat-sealing.

Figure 3 is a cross-sectional view corresponding to s Figure 2 showing the appearance of the package when finally heat-sealed.

Figure 4 is a cross-sectional view of the open end of the package as it would appear when in position .1 for sealing and air evacuation on the apparatus of the invention.

flat-unwrinkled condition and before the evacuation of the package under vacuum pressure conforming it to of the product and comprises the steps of placing the product within the container between the enveloping sides, applying heat and pressure to the unsealed margins of the container along the access opening to heat-seal a major portion of the opening and conform the remaini ing unsealed portions of the margins about the exterior of arigid fiuid conducting member to establish an airtight seal therebetween, applying a fluid pressure to the interior of said container, and finally applying further heat and pressure to the remaining unsealed portions of Figure 5 is a cross-sectional view of the showing of Figure 4 to illustrate the relative position of the air exhaustion nozzle, the opposed heat-sealed lips of the package, and the upper and lower pressure jaws.

Figure 6 is an enlarged detail view in section to diagrammatically illustrate the relative position of the upper and lower pressure jaws and the air evacuation nozzle as they are being applied to the open edge of the package of Figure 1 with the first-main sealbein-g made andjthe the contours of the products.

Figure 7 is a diagrammatic view in plan of the topof thepackage of Figure 1 to illustrate the condition of the seal as the air exhaustion nozzle is partially withdrawn.

Figure 8 is a cross-sectional View of the package shown in Figure 7 along the line 88 to illustrate the complete air-tight seal under the influence of the top and bottom pressure jaws and after the secondary heat-sealing pressure bar is applied with the air exhaustion nozzle par tially withdrawn. t i

Figure 9 is a cross-sectional view corresponding to the line 99 of Figure 7 to illustrate the relative position of the upper and lower main pressure jaws and the auxiliary heat-sealing jaw after completion of the heat-sealing operation with the air evacuation nozzle withdrawn from the path of the secondary jaw.

Figure 10 is a view in plan of the apparatus of the invention by means of which the sealing of the package, as illustrated in Figure 1, is accomplished.

Figure 11 is a view in front elevation of the apparatus of the invention.

Figure 12 is a cross-sectional view in end elevation of the upper portion of the apparatus shown in Figures 10 and 11 to illustrate more clearly the relative positions of the top and bottom pressure jaws and the actuating mechanism, with the air exhaustion nozzle shown in extended condition and the sealing jaws raised.

Figure 13 is a view corresponding to Figure 12 with the sealing jaws shown in closed condition and the air exhaustion nozzle withdrawn from the path of the secondaryjaw.

Figure 14 is an enlarged diagrammatic detail view along the line 14-14 of Figure 12 to illustrate in more detail the relative position of the foot pedal shaft and the associated controlling switches mounted on the supporting frame.

Figure 15 is an enlarged diagrammatic view partially in section and in plan of the construction shown in Figure 12 along the line 1515 to illustrate more clearly the relative positions of the actuating elements.

Figure 16 is a detail view of the internal arrangement of the control box mounted on the left-hand side of the construction shown in Figure 11.

v Figure 17 is a diagrammatic view of the electrical circuit controlling the apparatus of the invention.

With particular reference to Figures 10 and 12 of the drawings, a preferred embodiment of an apparatus in accordance with the present invention includes a main supporting frame or casing 10 on which there is mounted the sealing jaws 12 and 14 under the control of a foot pedal 16 supported from a pivotally mounted shaft 18. The jaw 14 is mounted directly to the top portion of the frame 10, while the jaw 12 is mounted on a supporting plate 19 for pivotal movement towards. and away from the jaw 14. The fixed jaw 14 includes a facing 20 of heat resistant resilient material, for example silicone rubber, and the jaw 12 is also provided with a similar resilient insert 21. The jaw 12 is heated electrically, as will be described in more detail later.

The supporting plate 19 is pivotally mounted, as indicated at 22, to the base 15 of the jaw 14. The rear end of the plate 19 is provided with an adjustable contact wheel 24 which is engaged by a cam-shaped lever end 26 connected to the end of the foot pedal shaft 18. The swinging motion of the foot pedal shaft 18 relative to the frame 10 causes, through contact of the lever end 26 with the roller 24 and pivotal motion of the plate 19, the jaws 12 and 14 to come together or re-open. The opening movement of the jaws is resiliently biased by a coil spring J30 placed between the plate 19 and the jaw base 15.

In addition to the jaw 12 an auxiliary sealing jaw 32 is mounted on the supporting plate 19. The jaw 32 is mounted on a supporting bracket 34 pivotally connected to a lever arm 36 which in turn is pivotally supported above the plate 19 by a connection with a standard 38 extending from the upper surface of the plate 19. The end of the lever arm 36 remote from the jaw support 34 is connected to an electrical solenoid 40 mounted in a suitable supporting frame 42 on the upper surface of the jaw supporting plate 19. When electrically energized the solenoid 40 acts to depress the auxiliary jaw 32 downwardly into sealing relationship with the plastic bag, as will be described in more detail later.

A fluid conducting nozzle or conduit is mounted for sliding movement on the jaw base 15 between a first position where it protrudes beyond the face of the jaw 14, see Figure 12, and into the interior of a bag or envelope to be sealed and a second position, see Figure 13, where it is withdrawn to a point clearing the downward path of the secondary jaw 32. The air exhaustion nozzle 50 has a somewhat hemispherical shape in cross section with a fiat bottom portion and a rounded top portion which makes for a better vacuum-proof seal between the top 12 and bottom 14 jaws and the nozzle member. This is shown in Figure 5.

The reciprocal movement of the nozzle 50 is accomplished by a mechanical linkage wherein a first lever arm 60 connected directly to a fluid connection block 51, from which the nozzle 50 extends, is pivotally linked by a connecting lever arm 62 to a further solenoid 70 mounted on the upper face of the supporting frame 10, as shown best in Figures 10 and 11.

The connecting link arm 62 is provided with switch activating projections 63, 65, which are adapted to contact mercury switches 98, 99, mounted in the path of the lever arm 62 when retracted, and which act to control the solenoid 70, as will be described in more detail later.

A vacuum connection is made to the fluid connection block 51 through a first conduit portion and a flexible conduit portion 82 which extends through a fixed conduit portion 84. The conduit portion 84 passes through the top surface of the supporting frame 10 and containues downwardly to a connection with a vacuum pressure pump driven by a suitable electric motor 92.

To give a visual indication and check of the vacuum pressure applied a by-pass conduit 85 is connected into the conduit 84 and a pressure gauge 86 is attached to this conduit. In the preferred construction, and to avoid possible clogging of the conduit 84 and/or the vacuum pump 90, a trap 94 is connected into the conduit 84 so as to screen and trap any foreign matter or portions of food products which might be withdrawn from the interior of the bag during the air evacuation operation.

The functions of the various portions of the apparatus described are mainly controlled through the control box 100, in the construction shown mounted on the side of the supporting frame 10, suitable dials and switches are provided whereby the machine may be initially set in operation and the degree of heat required in the pressure jaws pre-set before the sealing operations.

The interior of the control box is shown generally in Figure 16 wherein indicates a time delay control relay, 112 indicates a further time delay control relay, 114 indicates a vacuum switch, and 116 indicates a vacuum valve controlled by the vacuum switch 114. The general arrangement and connections between the co n trolling elements described and the oif/ on switches shown inthe front view of the apparatus are shown diagram matically.

Details of the circuit interconnecting these elements are shown diagrammatically in Figure 17. I

In order to prepare the apparatus for sealing a main control switch 140 is actuated as is also a heater switch 142 energizing heating elements in the upper jaw 12 and the auxiliary jaw 32. These are controlled by a thermostat 144 which can beset to the correct sealing temperatures for varying container materials. H

To explain the operation of the apparatus with reference to the preceding description, the operator places a pre-loaded bag between the jaws 12 and 14 making sure that the nozzle 50 is in extended position and is inserted between the opposed lips of the bag forming the access opening.

The foot pedal 16 is depressed which, as shown in Figures 12, 13 and 14, causes a first control switch to be contacted by an extension 17 of the foot pedal shaft 18. This first contacting of the switch 120 sets up the circuit to the solenoids controlling the subsequent motion of the auxiliary sealing jaw 32 and the partial withdrawal of the nozzle 50.

The depression of the foot pedal 16 through the shaft 18 also causes the opposed jaws 12 and 14 to come together making a seal across the mouth of the bag, as shown generally in Figure 4, and at the same time the resilient insert 21 on the upper jaw 12 and the resilient facing 20 on the lower jaw 14 mold the package into the contours of the nozzle 50, making a vacuum-proof seal between the bag and the nozzle. The continued pressure on the foot pedal 16 carries the pedal shaft 18 to a point where it contacts a second controlling switch 122 mounted on a bracket 124 beneath the top surface of the supporting frame and in alignment with the path of the foot pedal shaft 18.

The actuation of the switch 122 completes the circuit to the solenoid vacuum valve 116 which opens the line from the vacuum pump to the air evacuation nozzle 50. Air is withdrawn from the interior of the bag through the nozzle 50 until a pre-set vacuum is reached. When this vacuum pressure is reached, approximately 27-29 inches, the vacuum switch 114 closes automatically and sets the delay switch 110 which is a time delay relay preferably set for approximately of a second. When the time delay relay switch 110 operates the circuit is completed to the solenoid 70 and through the mechanical linkage previously described the nozzle 50 is withdrawn to the position shown in Figures 9 and 13 clear of the downward path of the auxiliary jaw 32. As the nozzle 50 moves to the end of its outward stroke, the first micro switch 98 is contacted by the stop 63 of the lever arm 62 and the solenoid 40 is actuated causing downward movement of the auxiliary sealing bar 32. At the same time, the stop 65 contacts the second micro switch 99 and this energizes the second time delay relay 112. The time delay relay 112 holds the secondary sealing jaw 32 in contact with the bag until a fluid-proof seal has been made directly in advance of the withdrawn nozzle 50 so as to complete the seal of the bag. The time delay switch 112 then acts to release or de-energize the solenoid 40 as the seal is complete.

The operator then releases the foot pedal 16 so that the jaws 12 and 14 are raised, permitting removal of the bag. The release of the switch 122 and the further actuation of the switch 120 acts on the solenoid 70 to return the nozzle 50 to its extended ready condition and re-arm the circuit respectively.

Preferably, although it is not necessary to make a complete seal, the operator reinserts the portion of the seal, which was slightly deformed as shown in Figure 5 to accommodate the nozzle 50, in one end of the pressure jaws remote from the nozzle 50, and with a quick pressure stroke flattens and seals this portion of the bag.

As previously mentioned, while only one air exhausting nozzle 50 is shown there could be two or more similar nozzles utilized in the apparatus of the invention. For example, two could be used in spaced apart relationship, one of which would evacuate the air and the other could be used as a discharge nozzle for powder or fluid, or any material which could be automatically drawn into the bag by the evacuation of air from the interior. It is also contemplated that the present method of performing a leak-proof seal on a plastic type bag could be utilized in combination with a similar nozzle or nozzles without applying vacuum pressure to the bag. For example, the leak-proof seal described could be made and a liquid could be injected into a container of this nature. With respect to food products, for example dill pickles in brine or anything of that nature which lends to packaging in a plastic envelope rather than in the usual glass bottle or jar might be prepared in accordance with the present invention. Further, a dry powder might be inserted in this type of plastic bag either in combination with the evacuation of the air or merely by injection, for example, some forms of medical preparations in powder form could 6 be packed "in flexible moisture-proof containers'iri this manner instead of utilizing the usual glass jar or vial.

The main feature of the present invention resides in the fact that most of the necessary heat-seal is performed prior to the application of fluid pressure to the interior of the bag, whether this be in the form of a negative pressure by a vacuum pump or if a liquid or other material is inserted in the package without vacuum pressure. The performing of the heat-sealing operation prior to the air evacuation permits a most eifective leak-proof seal to be made as compared with the seals made on other articles of this nature from which the air has first been evacuated.

I claim:

1. A heat-sealing and fluid pressure applying apparatus comprising a pair of opposed resiliently faced sealing jaws, one fixed and one movable above and in alignment with said fixed jaw, an auxiliary sealing jaw mounted for reciprocal movement on the forward face of said movable jaw, means for heating said movable and auxiliary jaws, a fluid conducting nozzle mounted for movement relative to said fixed sealing jaw with one end normally extending between said jaws into the path of said auxiliary jaw, means for actuating said movable jaw, auxiliary jaw, and fluid conducting nozzle, and control means connected to said actuating means, whereby said movable jaw is adapted to be actuated into sealing contact with said fixed jaw, said nozzle withdrawn from the path of said auxiliary sealing jaw, and said auxiliary jaw reciprocated in sealing engagement with said fixed jaw in time related sequence.

2. A heat-sealing and fluid pressure apparatus, as claimed in claim 1, wherein said movable jaw actuating means comprises a foot pedal and pivotally connected linkage members between said pedal and jaw, and said auxiliary jaw and nozzle actuating means comprise electrical solenoids with pivotally connected linkage members between said solenoids and said auxiliary jaw and nozzle.

3. A heat-sealing and fluid pressure applying apparatus comprising in combination, a supporting frame, a pair of sealing jaws having resilient facings mounted on said frame in opposed relationship, one of said jaws being movable and the other fixed relative to said frame, a first actuating means connected to said movable jaw, an auxiliary sealing jaw mounted on said movable jaw, a second actuating means connected to said auxiliary jaw, means for heating said movable and auxiliary jaws, at least one fluid conducting nozzle mounted on said supporting frame for sliding movement towards and away from said opposed sealing jaws, and having one end normally disposed between said sealing jaws, an actuating means connected to said fluid conducting nozzle, a source of fluid pressure connected to said fluid conducting nozzle, and control means mounted on said supporting frame and connected to said first, second, and nozzle actuating means whereby and in time related sequence said movable jaw is adapted to be moved into sealing contact with said fixed jaw and said extended nozzle end, said nozzle end partially withdrawn to clear said auxiliary sealing jaw and said auxiliary sealing jaw moved into sealing contact with said fixed jaw directly in advance of said withdrawn nozzle end.

4. A heat-sealing apparatus, as claimed in claim 3, wherein said movable sealing jaw is mounted on one end of a jaw supporting plate pivotally mounted above said fixed jaw, and said first actuating means comprises an adjustable pressure wheel mounted on the end of said supporting plate remote from said jaw and a foot pedal shaft is pivotally mounted on said supporting frame with one end provided with a rocker cam engaged with said jaw supporting plate pressure wheel.

5. A heat-sealing apparatus, as claimed in claim 4, wherein a lever arm is pivotally mounted on a supporting standard fixed to said movable jaw supporting plate,

said auxiliary jaw being pivotally connected to one end of said lever arm, the other end of said lever armbeing pivotally connected to an electrical solenoid constituting said second auxiliary jaw actuating means.

6. A heat-sealing apparatus, as claimed in claim 3, wherein said fluid conducting nozzle is slidably mounted in a supporting block and is pivotally connected by a mechanical linkage to an electrical solenoid constituting said nozzle actuating means.

7. A heat-sealing apparatus adapted for use in combination with an air evacuation nozzle for forming a vacuum in a heat-scalable bag containing a food product or the like, comprising a pair of opposed sealing jaws mounted for movement towards and away from sealing engagement with each other, an auxiliary jaw mounted on one of said opposed sealing jaws for movement towards and away from sealing engagement with the other of said jaws, said air evacuation nozzle being mounted for movement relative to said opposed sealing jaws and being normally disposed with one end extending beyond said jaws, means adapted to move said opposed jaws into sealing engagement with said nozzle end sealed therebetween, means to retract said nozzle end between said jaws while said jaws remain in sealing contact, means to move said auxiliary jaw into sealing contact with the said one of said jaws directly in advance of said re tracted nozzle end, and control means adapted to regulate said jaws and nozzle movements in time related sequence. 7

8. A heat-sealing apparatus, as claimed in claim 7, wherein said air evacuation nozzle is connected to a source of vacuum pressure and said control means actuates said source in sequence after said sealing contact of said first opposed jaws and maintains said applied vacuum pressure until said auxiliary sealing contact is complete.

9. A heat-sealing apparatus, as claimed in claim 7, wherein one of said opposed jaws is fixed and the other is movable and said auxiliary sealing jaw is mounted on said movable jaw.

References Cited in the file of this patent UNITED STATES PATENTS 1,970,193 Riebel Aug. 14, 1934 2,676,440 Campbell Apr. 27, 1954 2,712,208 Campbell July 5, 1955 2,749,686 Lorenz et al June 12, 1956 2,780,043 Hensgen Feb. 5, 1957

Images