US 2749686 A
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June 12, 1956 E. H. LORENZ ET AL VACUUM PACKAGING MACHINE 6 Sheets-Sheet 1 Filed Sept. 26, 1951 INVENTORS EDWARD H. LORENZ THOMAS WALJGH DONALD G MERRILL BY QM/kw @4151 AT TOR NEYS June 12, 1956 E. H. LORENZ ETAL 2,749,686
VACUUM PACKAGING MACHINE 6 Sheets-Sheet 2 Filed Sept. 26. 1951 HI- sw em w RO UE E O A N T W .vR NH o E G T mo T A o WH W 5% I NN June 12, 1956 E. H. LORENZ ETAL 2,749,686
VACUUM PACKAGING MACHINE Filed Sept. 26, 1951 6 Sheets-Sheet 3 AT TOR NEYS E. H. LORENZ ETAL 2,749,686
VACUUM PACKAGING MACHINE June 12, 1956 Filed Sept. 26, 1951 6 Sheets-Sheet 4 /5 INVENTORS EDWARD H. LORENZ THOMAS WAUGl-l DONALD 3. MERRILL BY M 'FM ATTORNEYS June 12, 1956 E. H. LORENZ ET AL 2,749,686
VACUUM PACKAGING MACHINE Filed Sept. 26, 1951 6Sheets-Sheet s INVENTORS EDWARD l-i. LORENZ THOMAS WALJGH DONALD (3. MERRILL ATTORNEYS June 12, 1956' Filed Sept. 26, 1951 6 Sheets-Sheet 6 F K3. IO TILT swncn L EMERGENCY w STOP SWITCH j 51 GRIPPERS T i i 4 DO N OPEN 5 1 @2 /33 I l I l mu! LIMIT SWITCH GRIPPERS I M I 7 VALVE Gi -E W 6; kw 6 1 q I l SEAL BAR B-i,1 T JNS 1 7 w gm v c #4 'r M sgLz N o o I /j 4Z0.
6 57 fgiRELAY gums DELAY RELAY 58 ST RT SWAITCH My RESISTOR FUSEM /J a \-g M0 50 i rill THERMOSTAT THERMOSTM; RES'STQR HEATER I a no VOLTS TOP N/#15 3 HE'KTER Il E ,1 /4 j BOTTOM /45 1 37 9 34 HEATER W LAMP LAMP FUSE/pi INVENTOQS EDWARD H. LORENZ THOMAS WALJC: DONALD G. MERR l L L ATTOR NEYS United States Patent VACUUM PACKAGWG MAC Application September 26, 1951, Serial No. 248,412
17 Claims. (Cl. 5322) The present invention relates to improvements in vacuumizing and sealing bags and similar flexible containers.
Substantial disadvantages reside in methods and apparatus heretofore used or proposed for packing in bags and particularly those formed of heat scalable films of polyethylene and other thermoplastic materials.
These films conform readily to irregular surfaces and when air is evacuated from bags formed of them, the film closes against the suction or evacuating nozzle passages and frequently prevents removal of air from more remote parts of the bag.
Difiiculty also has been encountered in effectively sealing such bags while maintaining a vacuum and in avoiding imperfect seals.
It is an object of the present invention to overcome these and other difficulties by providing a bag packaging machine having an improved suction device for exhausting air from a bag quickly, completely and with minimum waste of bag stock.
A further object is the provision of a machine of the type indicated which is adaptable to a wide range of bag sizes with minimum adjustment and which is suitable for packaging contents of varying shapes.
Another object is to provide sealing apparatus which effectively seals without appreciable loss of vacuum and with little or no wrinkles along the sealing line.
Still another object is to provide an evacuating and sealing device in which the product is held away from the evacuating nozzle and tension applied on the bag during evacuation to prevent the film drawing in and closing off the evacuating ports and the tension is relieved between the sealing line and the product just prior to and during sealing.
A further object is to provide a machine of the type indicated in which the waste is automatically severed from the bag proper at the seal and automatically removed from the head assembly 4 upon completion of the bag evacuating and sealing operations.
These and other objects of the invention will become more apparent from a study of the following description which is made with reference to the accompanying drawings, in which:
Fig. l is a side elevation view in part broken away and in part sectioned of packaging apparatus embodying the invention;
Fig. 2 is a top plan view of the apparatus shown in Fig. 1;
Fig. 3 is a view of a portion of the apparatus shown in Fig. 1 but with the sealing bar down, the evacuating head tilted, and the tongue and spreader bars retracted;
Figs. 4-7, inclusive, are perspective views showing successive steps in the operation of the apparatus of Figs. 1-3, inclusive;
Fig. 8 is a cross-sectional view of the vacuum head taken substantially on line 3-8 of Fig. 2, showing the vacuum line connection and adjustable throttle;
Fig. 9 is a cross-sectional view of a part of the food tray or table portion and its adjustment means; and
Fig. 10 is a somewhat schematic wiring diagram of the device illustrated in Figs. 1-9, inclusive.
GENERAL DESCRIPTION Referring to the drawings, the embodiment of the invention there illustrated generally consists of a vacuum packaging machine having a movable packaging table generally designated 1 and associated movable stop 2 which holds the plastic film or other sheet material of a bag 3 taut with respect to a vacuumizing head assembly, generally designated 4. The head assembly includes a nozzle 5 and a pair of spreader bars 6 (Fig. 4) over which mouth 3a of the bag 3 may be drawn and there after stretched by the bars 6 and clamped by resilient jars 7a, 7b, as shown in Figs. 1, 3 and 5.
An air evacuating or vacuumizing tongue 8 for removing air and collapsing the bag 3 about the product 9, such as meat loaf or the like, packed therein, is operably mounted in the nozzle 5 for retraction with the spreader bars 65 from their forward positions shown in Figs. 2 and 5 to a retracted position relative to the nozzle 5 where they clear the path of a movable heat-sealing bar unit, generally designated 1%, which with a stationary unitsealing unit generally designated 11, grips and seals the bag 3. As is shown in Fig. 3, the vacuumizing head assembly including the clamping jaws 7a, 7b, are retractable as a unit from the sealing units it) and 11 to tear off the unused portion 3b of the bag between the sealing bars and the clamping jaws.
DETAILED DESCRIPTION Movable packaging table Referring more particularly to the details of the vacuum packaging machine illustrated, there is provided a frame, generally designated l2, which includes corner posts 13 and a stationary horizontal table 14 above which the two-spaced halves of a second or work table 15 are adjustably mounted relative to the table 14 by means of suitable slotted depending side brackets 16 and wing nut and boit fasteners 17 (Figs. 1 and 9). As shown in Fig. 2, the two spaced halves of the table 15 are joined by front and rear bars 13 and 19, respectively, which slidably support a movable table 20 for moving the packaged product 9 toward the sealing units 10 and 11. Fastened to the underside of the table 2d are a pair of spaced depending bearing blocks 21, 22, which are slidably mounted on a bearing rod 23 fastened at its ends to the bars 18 and 19 and restrict the table 2t? to axial movement with respect to the vacuumizing nozzle 5.
The table 20 is spring pressed away from the nozzle 5 by a compression spring 23a located about the rod 23 and compressed between the bearing block 22 and a collar or washer 24- fastened to the rod 23.
Movement of the table 2% toward the nozzle 5 is effected by a transverse pull bar 25 (Fig. 2) which is centrally fastened to the block 22 and to the ends of which are pivotally secured the rear ends of a pair of tie rods 26. As shown in Fig. l, the forward ends of each of the rods 26 has a rigid right-angle projection 26a which is pivotally secured to an arm 27a of hell cranks 27. The latter are adjustably clamped to the ends of a rod 28 which, as shown in Fig. 2, is disposed transversely of the table 14 and is rotatably journaled in bearings 29 fastened to the table 14. Arms 27!; of the bell cranks 27 are depressable by means of pins 30 (Figs. 1, 4 and 7) which move with the heat-sealing unit It) and rotate the bell cranks 27 in the clockwise direction (Fig. 1) to draw the table 2% forwardly to the position shown in Figs. 3 and 6 so as to shorten the distance and slack the bag between the nozzle 5 and the table 20 and stop 2. As shown in Figs. 1 and 2, the stop 2 is secured to the shaft 28 for pivotal movement therewith and with the table 3 just prior to heat sealing of that portion of the bag between the sealing units 10 and 11.
Prior to engaging and depressing the crank arms 27b, the pins 30 each first engage and rotate counterclockwise from latching engagement (Fig. 1) with detents 32 se cured to table 14, latching pawls 33 which are pivotally carried on the ends of crank arms 27b and, in the latched position shown in Fig. 1, restrain the movable table 20 and the stop 2 in their rear positions (Figs. 1, 2, 4 and 5).
The clockwise rotation (Fig. 1) of the bell crank 2'7 and the resulting forward movement of table 20 is limited only by engagement of the sealing units and 11. Accordingly, the pins 30 are adjustably secured relative to the upper sealing unit 10 with which they move, so that they reach the position corresponding to the foremost position desired for table 20 when the sealing unit 10 reaches its lowermost position in engagement with the lower sealing unit 11.
For larger packages, an alternative stop 2 (phantom Fig. 1) may be secured to the table 20 and substituted for stop 2 in positioning the bag 3 and its contents 9 so as to prevent the package from moving forward on the table 20 when the tongue 8 is retracted. The illustrated stop 2' is merely representative of suitable means for preventing forward slippage of packages on the table 20 and may be used with suction grippers, positive hold-down means, or other positioning means (not shown) for holding the packages against slippage on the table.
The stop 2 also holds the food or other product 9 back from the sealing line, restraining the tenden y of the package to pull up to the nozzle 5 when suction is applied and the tongue 8 is retracted. Despite its anti-friction coating, the withdrawal of the tongue 8 and spreader bars 6 pulls hard on the bag, setting up a further tension which helps to keep the film from drawing into the evacuation ports. Although found to be less desirable, the pivoted stop 2 shown in the drawings may be replaced by a ledge underneath the bag, which rises after the bag is placed and lowers after the tongue is withdrawn, to relax tension before sealing. Relieving of tension just before sealing is especially important when sealing films which shrink with the application of heat.
Heat sealer As shown in Figs. 1-3, the lower heat-sealing element, generally designated 11, is secured to and extends transversely of the table 14 between the latch detent members 32. While the details of the element 11 may vary considerably, in the preferred form illustrated it includes an electrically heated metal bar to the upper horizontal sealing surface of which a non-sticking pad 35, of silicone or other non-sticking material, may be secured as by means of gibs 36 and suitable adhesive.
Similarly, the upper heat sealing unit 10 includes an electrically heated metal bar 37 which is secured to a channel-bar crosshead 38 for movement into and out of sealing engagement with the resilient pad 35 of the lower sealing element 11.
As indicated in Fig. 1, the upper bar 37 is operably secured adjacent its ends to the upper ends of a pair of vertically disposed posts 39 and 41 which are secured at their lower ends for simultaneous axial reciprocation between the upper and the lower or sealing positions shown in Figs. 1 and 3, respectively, by a suitable connecting yoke 41 and operating piston 42.
Preferably, a lost motion spring 43 is provided on the upper end of each of the posts 39 and 40 which permit slight movement of the upper element 10 relative to the posts so as to accommodate for over-travel of the posts below the sealing engagement position (Fig. 3) of the sealing elements. Thus, the sealing pressure applied by the cylinder 42 to the upper element 10 is resiliently exerted through the compression springs 43 rather than through rigid engagement of the posts 39 and 40 with the element 10 and the crosshead 38 to which it is secured 4 and assures uniform seating of the top bar 37 on the bottom bar 34.
It also is desirable to cushion and limit the final upward opening travel of the element 10. Accordingly there may be secured to the cross-yoke 41 a pair of upwardly projecting spaced rods 44 on each of which is located a coil spring 45 which is placed under compression between table frame member 46 and an annular shoulder 44a of each rod 44 as the element 10 approaches its upper position (Fig, 1) thereby resiliently snubbing its final upward travel. The top of the upstroke is limited by engagement of the top of the rod 44 with the table 14.
Preferably the hot sealing bars 34 and 37 are provided with insulating housing or casing members generally designated 47 and 48, respectively, in the drawings, and with the stop 2, which may be provided with insulation on its under surface aid in maintaining a preselected sealing temperature for the elements.
Temperature conrtol of the heat-sealing elements may be individually controlled, as by means of adjustable thermostats 49 and 50, respectively in the circuit (Fig. 10) supplying current to the heating elements. The manual adjustment knob for thermostat 50 is shown at 50a (Fig. 4) and the knob (not shown) for element 49 is directly above 50a but within the housing 48.
Vacuumizing heaa'n0zzle The vacuumizing head 4 has four principal components, namely, the nozzle 5, spreader bars 6, clamps 7a, 7b, and tongue 8.
As shown in Figs. 1-4, the nozzle 5 is a shaped member of generally oval cross-section and is horizontally disposed so that an operator readily may manually draw the open mouth 3a of the bag 3 over the nozzle 5 and over the spreader bars 6 when the nozzle and bars are positioned as in Fig. 4.
The width of the nozzle 5 is less than that of the narrowest bag to be handled. The edges 5a of the nozzle sharply taper to form acute angles which permit the sides of the bag to meet closely at the edges during vacuumizing even when the bag is under some lateral tension.
The nozzle 5 is secured to a plate P which, as is hereinafter described in greater detail, is mounted for pivotal tilting movement between the positions shown in Figs. 1 and 3 by means of a bearing bracket P which is rotatable on a shaft 51 journaled in spaced bearings of a bracket 51 fastened to the table 14.
Vacuumizing headretractable tongue The vacuumizing tongue 8 is slidably mounted within the nozzle 5 and, as shown in Fig. 2, is secured to the forward end of a rod 52 by means of which the tongue is advanced and retracted relative to the nozzle 5 between the positions shown in Figs. 1 and 3.
Preferably the tongue 8 is covered or coated with a layer of polytetrafluoroethylene, chromium, or other antifriction material, over which materials, such as polyethylene, rubber hydro-halides, vinyl and vinylidene halides and other heat-scalable plastic film of which the bags 3 preferably are formed, will readily slip.
Preferably the tongue 8 extends almost to the product within the envelope 3 (Fig. 5) so that the product 9 does not engage and cover the evacuating passages 53 while, at the same time, the bag film has only a short distance to bridge between the product 9' and the tongue 8 and cannot be drawn in to close the passages 53 when tensioned between the clamps 7a, 7b, and the stop 2. However, the tongue 8 may be employed as a stop for the product 9, and when so employed, the end of the tongue preferably is beveled so that only the leading edge engages the product and the vacuum openings 54 cannot be closed and clogged by the product.
Another preferred arrangement is to adjust the height of tables 15 and 20 relative to the tongue 8 so that the tongue on its forward position is slightly above and overlies the leading end of the product 9. The latter arrangement also has been found particularly satisfactory in preventing clogging of the tongue passages 53 by the bag wall during vacuumizing. When so disposed, it is preferable to provide additional vacuum openings (not shown) on the underside of the tongue.
The tongue 8 preferably is tapered and rounded as shown in Fig. 4, to minimize wrinkles left in the mouth of the bag when the tongue is withdrawn.
Evacuation of air from the bag 3 is effected through central passages 53 and side openings 54 in the front end of the tongue which communicate through passages 54 with nozzle chamber 55 (Figs. 2 and 8) that is connected through a passage 56 and vacuum line 57 with a source of vacuum such as a tank T which is connected to a suitable evacuating pump 143 (Fig. the volumetric displacement per second of which preferably is at least 10 to times the capacity of the bag 3.
Beneath the generally oval-shaped portion of the nozzle 5, as shown in Figs. 1, 2 and 4, a horizontally disposed push bar 59 is secured to cranks 6*!) which are fastened on a shaft 61 journaled in bearings 62 secured to the plate P. Pressure exerted on the bar 59 by the operator following positioning of a bag mouth 3a over the nozzle pivots the cranks 6t} and causes a crank arm 63 fixed to the shaft 61 to depress pin 64 which closes a switch 65 and thereby energizes solenoid 66 (Figs. 3 and 10) which connects vacuum line 57 through a valve 57a with the vacuum tank T.
As shown in Figs. 1 and 3, the solenoid 66 is fixed to a bracket 69 which is fastened to the stationary table 14 and has a vertically depending armature 66a which is connected by link 67 with a bell crank 68 pivotally mounted on the bracket 69. Crank arm 68a has a latching notch 68b which normally underlies the cross bar 41 and acts as a safety catch which prevents premature descent of the hot sealing unit 10.
However, when manual pressure is exerted on the push bar 59 following positioning of the bag mouth 3a about the nozzle 5, the solenoid 66 is energized and the armature 66a drawn upwardly moving the bell crank to unlatched position (phantom Fig. 3) so as to leave the sealer unit 10 free to move to its lower or sealing position.
Concurrently, arm 680 of the bell crank 68 operates through link 76) to turn the crank 57b and open the vacuum valve 57a so as to connect the nozzle 5 through line 57 with the vacuum tank T.
Preferably the vacuum line 57 can be adjustably throttled as by means of the adjustable valve pin 58 (Fig. 8) so that evacuation of air from the bag 3 through the nozzle 5 is gradual even though high vacuum is maintained at the tank T and eventually established in the bag 3.
Bag waste ejection The nozzle 5 also is provided with passages 71 (Fig. 2) which are connected by a high pressure air line 71a to a source of compressed air (not shown) for blowing the waste portion 3b (Fig. 3) of the bag off the nozzle 5, as shown in Fig. 7. The compressed air line 71a includes a control valve (not shown) which is automatically opened after each bag evacuating and sealing cycle by a solenoid or equivalent control means 71b (Fig. 10) so as to automatically blow the bag portion 3b from the nozzle.
If desired, the vacuum line 57 and the pressure line 71a both may be connected with the compressed air source so that when the bag end 36 is blown from the nozzle the compressed air discharges any food or other product which may have been drawn inadvertently into the tongue 8, nozzle 5, or vacuum line 57 during evacuation of air from the bag.
Also, if desired, both lines 57 and 71a be connected to the vacuum tank T so that air may be evacuated from the bag 3 through the passages 71 in the nozzle 5 as well as through the passages 54 in the tongue 8.
Clamping jaws As shown in Fig. 5, the clamping jaws 7a, 7b are adapted when closed to tightly clamp the bag walls to the nozzle 5, to the spreader bars 6, and to each other so that air cannot enter the bag while thus clamped and the full vacuum of the line 57 can be exerted in the bag.
Referring more particularly to Figs. 1 and 2, each clamp includes a resilient rubber pad 72a backed by a metal bar 72b which is secured at its ends to brackets 72c. Preferably the resilient clamping pads 72a of the jaws 7a, 7b are notched, as shown in profile in Figs. 1 and 3, so that the jaws each have a plurality of clamping surfaces 164, 105, which cooperate with corresponding surfaces of the other jaw to more firmly press and seal the bag about the nozzle 5 and bars 6. The thin portions of the pads 72a are adapted to fold close around the spreader bars so as to prevent leakage.
The brackets 720 for the lower jaw 7a are fastened to the forward ends of a pair of spaced levers 72 which are pinned to the ends of a transverse shaft 73 that is rotatably journaled in bearing blocks 73' on the tilt table or plate P.
The brackets 720 for the upper jaw 7b similarly are fastened to the forward ends of a pair of levers 74 which rotate on a transverse shaft 75 that is mounted on plate P.
As shown in Figs. 1, 2 and 3, the rear ends of the upper jaw levers 74 are operably connected by adjustable turnbuckles 77 with the lower jaw levers 72 so that upward movement of the lower jaw 7a from its open position to the clamping position shown in Figs. 1 and 3 is accompanied by downward movement of the upper jaw 7b from its open position (phantom Fig. l) to its clamping position (solid line, Fig. 1). By adjusting the turnbuckle 77, the jaws 7a, 7b can be adjusted to meet properly at the side edges 5a of the nozzle 5.
Clamping pressure is applied by a cylinder 78 which is mounted by brackets 79 to a vertically depending channel member that is fixed to the tilt plate P.
As shown in Fig. 1, piston rod 78a is connected by a link 81 with lever 82 which is keyed to the shaft 73 on which the clamping jaw levers 72 pivot. Air pressure for operating the cylinder motor 78 is supplied by a line 83 through a spool valve 84 operated by a solenoid 85 which (as shown in Fig. 10) is energized by manually closing the two series connected starter switches 86, 87 (Figs. 4 and 10). The wiring circuit is described hereinafter in greater detail. However, for the purpose of describing the operating components for the clamping jaw, it is sufficient at this point to explain that the closing of switches 86 and 87 energize a relay 83 which includes a relay switch 89 that keeps the relay energized after the self-opening switches 86, 87 are released, and a relay switch 90 which connects the valve solenoid 85 (Fig. 1G) with current and operates the associated valve so that the cylinder motor 78 operates to close the jaws 7a, 7b.
When the jaws reach their closed position (Fig. l) a normally closed limit or micro-switch 91 mounted on the motor 78 is opened by the pressure of a screw 92 which is adjustably carried by the piston rod 78a so that the valve solenoid 85 is deenergized and air bleed, which occurs at the valve 84 when the solenoid 85 (Fig. 10) is energized, is discontinued while pressure is maintained in the cylinder 78 so as to hold the jaws 7a, 7b, clamped as in Fig. l.
Spreader bars The spreader bars 6 are members which automatically spread apart to stretch the bag 3 smoothly across the sealing space so that no laps or wrinkles occur in the seal, and in order not to interfere with descent of the sealing unit 10, are automatically retracted from the sealing space just prior to engagement of the unit 10 with the sealing unit 11.
As shown in Fig. 2, the spreader bars 6 are located on opposite sides of the evacuating nozzle and are detachably mounted in eyes 93 and 930 located in the ends of a pair of levers 94 which are mounted for horizontal pivotal movement on vertical posts 95 secured to the tilt plate P. Adjustment slots 96 in the plate P provide means for adjusting the spacing between the posts 95 so that the spreader bars 6 are at least parallel and preferably point out slightly when they are spread to the limit per mitted by the bag 3. Springs 97 are tensioned between the levers 94 and fixed arms 98 so that the bars 6 spread and resiliently stretch the mouth of the bag so as to eliminate wrinkles therein between the sealing units and 11. Proper adjustment of the bars 6 can be preset for a particular size bag by means of pointers 99 which indicate on scales 100 the bar spread for different settings of the posts 95.
The levers 94 each have bell crank portions 94a that carry rollers 101 which are normally engaged by arms 102a of bell cranks 102 so that the levers 94 and spreaders 6 point inwardly and fold close against the nozzle 5, as shown in Fig. 4, ready to receive the bag mouth 3a. However, as the jaws 7a, 7b, start to close following closing of switches 86, 87, the rear end of the jaw arms 72 which are connected by links 103 to belt crank arms 10% rotate the bell cranks 102 clockwise (Fig. 1) and the springs 97 spread the bars 6 (Fig. 2) as the rollers 101 are permitted by the crank arms 102 to move rearwardly so that the bars 6 reach their spread positions prior to full closing and clamping of the jaws 7a, 7b.
When spread they distend the bag to its full width. As they are spread by the spring, variations in width of bag are accommodated, and the tension may be adjusted as desired by suitable selection of the spring.
T ongzte and spreader bar retraction The tongue and spreader bars 6 are retracted out of the path of the heat sealing unit 10 by means of a bar 106 which extends transversely of the machine and is slidably supported on rails 107 which are secured by brackets 108 to the tilt plate P. The spreader rods 6 extend through slots 109 in the bar 106 and are provided with adjustable nuts or similar members 110 which cause the rods to move longitudinally responsive to movement of the bar 106 on the rails 107 without altering or modifying the spread of the bars 6.
The tongue rod 52 also is secured to the bar 106 by a pin 111 or other suitable fastener.
Retraction of the tongue 8 and spreader bars 6 is effected by forcing the bar 106 rearwardly on the rails 107 by means of a bell crank 112 having forked crank arms 112a, the ends of which carry rollers 113 located within shipper yokes 114 fastened to the bar 106. The bell crank 112 is pivoted on the shaft 51 and has an arm 11217 the end of which carries rollers 115 located between shipper collars 116 of a rod 117 for operating the bell crank 112 and thereby advancing and retracting the tongue 8 and spreaders 6.
As shown in Fig. 1, the rod 117 is slidably mounted for vertical axial movement in a cylindrical guide 118 located at the end of a bracket 119 secured to the operating shafts 39 and 40 of the upper sealing unit 10.
Downward movement of the sealing unit 10 and rods 39, 40, lowers the bracket 119 until a pawl 120 pivoted at 120:: to the bracket engages an adjustable threaded stop nut 117a on the lower end of the rod 117 whereupon further downward movement draws the rod 117 downwardly and retracts the tongue 8 and spreader bars 6 out of the path of the sealing unit 10 just prior to the descent of the unit 10 to the elevation of the tongue and spreaders.
In order to permit further downward movement of the sealer 10 into sealing engagement with the lower sealer unit 11, a striker plate 1200 pivots the pawl 120 out of engagement with the nut 117a. Preferably a spring 117b is compressed between the nut 117a and the bracket 119 by the final downward motion of the sealer 10 after the pawl is unlatched (phantom Fig. 3), thus resiliently holding the tongue 8 and spreaders 6 retracted during the sealing operation.
The balance of the pawl is such that it automatically pivots to its operative position against a pin 12% when it disengages the striker plate 120a upon upward movement of the sealer 10. Further upward movement of the sealer and the rods 39, 40 causes the top of the guide sleeve 118 to engage a collar 117e, which is pinned to the rod 117, and moves the rod 117 and the bell crank 112 so as to advance the tongue 8 and spreader bars 6 to their forward positions (Fig. 1).
Tilt table and seal trim In accordance with the present invention, the bag mouth 3a is trimmed from the bag proper at the seal. In the embodiment of the invention shown in the drawings, the trimming is effected by pulling the bag mouth 3a away from the hot sealed portion while the latter is held between the closed sealing units 10 and 11. More particularly, as shown in Fig. 3, the nozzle 5 together with the bag mouth 3a clamped thereto by the closed jaws 7a, 7b is moved away from the closed sealing bars 10 and 11 by tilting movement of the tilt plate P.
Tilting of the plate P is accomplished by a piston motor 121 which is secured to the table 14 and has a piston rod 122 connected by link 123 with the channel member 80 which depends from the plate P.
Air or other operating pressure medium is connected to the motor 121 by a solenoid operated valve (similar to the valve 84) the solenoid 124 of which is energized through a normally open tilt switch 125 (Figs. 1, 3 and 10) which is closed when the sealing unit 10 is lowered into sealing engagement with sealing unit 11 by pressure of a member 126 fastened to cross-bar 41, thereby causing the motor 121 to tilt up the plate P and the vacuumizing head 4 which it carries to the tilted position shown in Fig. 3.
When the piston rod 122 reaches the limit of the tiltup stroke, a normally closed micro or limit switch 129 is opened by an actuating button 130 adjustably secured to a bracket 131 fastened to the rod 122. As is apparent from Fig. 10, opening of the switch 129 deenergizes a relay 146 which was energized concurrently with the vacuum solenoid 66 and closed relay switch 146a so as to keep the relay 88 as well as the relay 146 and vacuum solenoid 66 energized after the operator removes manual pressure from the starter bar 59. With the opening of the tilt limit switch 129 and deenergization of the relays 88 and 146, the relay switches 90 and 146a remake the connections shown in Fig. 10 and with a normally open switch 127, which is closed when the sealing unit 10 is down by a striker 128 on the bar 41, energizes a tilt-down solenoid 132, a gripper opening solenoid 133 and a solenoid 134 for initiating upward or opening movement of the sealing bar unit 10.
More particularly, the solenoid 132 reverses the valve operated by solenoid 124 so as to supply the piston motor 121 with pressure medium which reverses the motor and returns the plate P to its tilt-down position (Fig. 1).
Similarly, solenoid 133 (Fig. 10) operates valve 84 to connect the air piston motor 78 with the air line 83 so that the clamping jaws 7a, 7b, are opened and the spreader bars 6 cammed inwardly to the position shown in Fig. 4.
Likewise, the solenoid 134 (Fig. 10) operates a valve (not shown) which connects the sealing bar piston 42 (Fig. 1) with the source of air pressure so that the sealing unit 10 is raised to its fully open position.
Bag mouth ejection Following initiation of the tilting which returns the plate P to horizontal position (Fig. 1), the camming inward of spreaders 6 and the opening of the clamping jaws 7a, 7b, the bag mouth remnant 3b (Fig. 7) is blown from the nozzle by compressed air discharged through nozzle openings 71 from the line 71a. The discharge is effected by momentary energization of the solenoid 71b (Fig. which momentarily opens the air valve (not shown) in the line 71a. Energization of the solenoid 71b is effected by a micro-switch 138 (Figs. 1 and 10) which is opened shortly following initiation of upward travel of the sealing bar 10 by a pressing member 139 carried by the cross bar 41.
ELECTRICAL CIRCUITS Heater and vacuum Referring more particularly to the wiring diagram (Fig. 10), the top and bottom heater elements 37 and 34 are respectively fed through variable resistors 140 and 141 and the thermo-switches 49 and 50. When the heaters 37 and 34 are cold, the thermo-switches 49 and 50 automatically close thereby applying full line voltage on the heaters through heater switch 142. When preselected temperatures corresponding to the settings of the switches 49 and 50 are reached, the thermo-switches open, reducing the heater voltage by an amount which depends upon the settings of the resistors 140, 141, the purpose of which is to prevent the sealing bars 10 and 11 from cooling too rapidly. If the temperature cycling on either bar is too rapid, for example more than once every three minutes, adjustment of the associated resistor corrects this condition.
Vacuum pump The vacuum pump 143 is controlled by a switch 143a which may be located with heater switch 142 on a suitable control panel (not shown). As is apparent from Fig. 10, the heater switch 142 must be on before the pump 143 will operate.
Operating circuit and operation Closing the start switch 144 (Fig. 10) energizes a control circuit line 144 and makes the machine ready for operation. The sequence of operation is as follows:
The operator places the filled bag 3 over the nozzle 5 and spreader bars 6 and concurrently presses the push bar 59 to close the vacuum start switch 65 which energizes and closes the relay 146. The relay holds itself closed by a shunting circuit which, as shown in Fig. 10, includes the normally closed tilt limit switch 129 and the relay switch 146a.
The vacuum solenoid 66 which is in parallel with flie relay 146 also is energized and raises armature 66a (Fig. 1) which pivots the bell crank 68 thereby opening vacuum valve 57a which starts evacuation of the bag 3 and unlatches the safety latch 68]), as shown in phantom in Fig. 3. The operator then pushes the two start buttons 86, 87, thus energizing the relay 88 and thereby closing relay switches 89 and 90, the former of which keeps the relay 88 energized through lines 147 and 148 after the start button switches 86 and 87 open.
Closing of the upper switch 90 of the relay 88 connects the gripper closing solenoid 85 through the normally closed gripper limit switch 91 and causes the gripper motor 78 to close the jaws 7a, 7 b, and operates the bell crank 118 to spread the bars 6 open and stretch the bag 3 at the area of sealing.
Concurrently, a time delay relay 150 in parallel with the relay 88 is energized and after a suitable time delay, the amount of which is previously set by adjustment so that the bag is completely evacuated, thereafter closes a relay switch 158a which with the relay switch 90 and the closed top limit switch 135 energizes a sealing bar closing solenoid 42a (Fig. 10) which operates a valve (not shown) so as to connect the piston motor 42 with air pressure and thereby draw the sealing bar unit 10 downward to the sealing position, Fig. 3.
A top limit switch 135 which is normally held closed by pressure of element 136 which is adjustably fixed to he post 39, opens as soon as downward movement of the sealing unit is initiated and the element 136 moves away from switch 135 so that the solenoid 42a is deenergized and air pressure is not bled from the valve which it controls during the remainder of the downward travel of the sealing unit 10.
As heretofore described, the descent of the sealing bar 18 elfects the retraction of the tongue 8 and Spreaders 6 and the table 20 and stop 2 are moved forward slacking the bag 3 at the sealing line. As the bar 41 reaches the bottom of its travel, it causes the strikers 126 and 128 to close the tilt switch and the bottom limit switch 128, respectively.
Closing of the tilt switch 125 energizes the tilt cylinder solenoid 124 (Fig. 10) which actuates its associated valve (not shown) so that air is supplied to piston motor 121 which causes the head 4 to tilt back to the position shown in Fig. 3 thereby tearing the excess mouth portion 3a from the bag 3 along the seal line. The length of time for the head to tilt back is controlled by an adjustment or throttling valve in the air line (not shown). The same valve also controls the time the sealing unit D is down, and, hence, the sealing time because, as the tilt cylinder reaches the maximum tilt, the normally closed tilt limit switch 129 is opened by the striker 130 (Fig. 3,. deenergizing the relays 146 and 88 (Fig. 10) and allowing the relay switches 146a, 89 and 90 to return to their normal positions which are shown in Fig. 10 thereby deenergizing the vacuum solenoid 66 and the time relay 150 and opening relay switch 150a. Thereupon the relay switch 98 with the temporarily closed bottom limit switch 128 connects line 145 with the tilt-down, gripper opening and sealing bar raising solenoids 132, 133 and 134, respectively, thereby operating their associated valves to connect their respective piston motors 121, 78 and 42 with air pressure 50 that the motors tilt down the vacuum head 4, open the clamping jaws 7a, 7b, and raise the sealing bar 10 to the positions shown in Fig. 1. As the sealing bar 10 rises, the end reject switch 138 is momentarily closed by the striker 139 and since relay switch 146a is in the normal position, shown in Fig. 10, the air vfive solenoid 71b is momentarily energized and causes a jet of air through the passages 71 to blow the bag waste 3b off the nozzle 5 and the now closed spreader bars 6.
As heretofore indicated, each of the air piston motors 42, 78 and 121 is provided with a valve assembly identical with 84, the movable valve portion of which is actuated by associated bleed valves that are solenoid actuated. The limit switches 92, 128, 129 and preferably are provided in order to prevent excessive air waste and are set to open as soon as the proper primary valve movement has been effected and the piston motor operation initiated. However, it will be understood that alternative solenoid or other automatically controllable valve structures may be employed.
For purposes of safety, it is necessary to be able to open the grippers 7a, 7b, and sealing bars 10, 11, anywhere in the machine cycle. For this purpose a safety bar 151 (Figs. 1 and 2) has been placed on the front of the machine. When it is pressed, it acts to open a switch 152 (Fig. 10) and deenergize the relays 146 and 88, thus allowing the relay switches to return to the normal positions shown in Fig. 10 and to energize the solenoids 132, 133 and 134, returning the tilt, gripper, and seal pistons 121, 78 and 42, respectively, to their normal or open positions, shown in Fig. 1.
Having thus described the invention, we claim:
1. In a machine for evacuating air from a bag containing a product to be packaged therein and for sealing the mouth of said evacuated bag containing the product, the combination of a nozzle for removing air from said bag including an extension tongue retractable into the nozzle, means for spreading the edges of the mouth of the bag about the nozzle and tongue, clamping jaws having resilient portions for pressing portions of the bag mouth against the nozzle and the spreader means and for holding closed the remaining portions of the bag mouth, means for sealing closed a spread portion of said bag, means for moving said tongue from the bag portion to be sealed, means for holding said product spaced from said clamping jaws with the portion of the bag therebetween under tension, and means for relieving said tension following the evacuation of the bag and the movement of said tongue and immediately prior to sealing by said sealing means.
2. A machine for packaging commodities in flexiblewalled open-mouth bags and withdrawing gases from the filled bags, including a hollow member smaller than and receivable within the mouth of said bag, said hollow member being adapted to be inserted into the mouth of said filled bag, means for resiliently engaging the sides of the bag and laterally tensioning the bag mouth about said hollow member, means 'for transversely flattening and gripping the walls of said mouth against themselves and against said member, means for evacuating gases from said bag, and means for transversely sealing a laterally tensioned portion of the bag mouth.
3. A machine as recited in claim 2 and including means for longitudinally tensioning the wall of the bag between the enclosed commodity and said flattening means.
a 4. A machine as recited in claim 3 and including means for relieving longitudinal and lateral tension on the sealed portion prior to scaling.
5. A machine as recited in claim 2 and including means for moving said gripping means away from the sealing means while the bag mouth is held by the gripping means and by the sealing means and thereby severing the bag mouth from the bag proper at the sealing line.
6. The method of packaging commodities in flexiblewalled open-mouth bags which comprises introducing a selected quantity of the commodity into the receptacle leaving a head space, withdrawing gases from said receptacle through a nozzle to cause collapsing of the walls of the receptacle and elimination of the head space, spreading and resiliently stretching the walls defining said head space in a first transverse zone removed from sm'd nozzle, flattening and gripping the walls of the mouth through a second transverse zone about said nozzle, and then sealing the receptacle along a transverse line in said first zone while the receptacle is in the last-mentioned condition.
7. The method recited in claim 6 and wherein the receptacle wall is longitudinally tensioned between the commodity and said second zone during evacuation of gases from the receptacle.
8. The method recited'in claim 7 and wherein said tension is relieved immediately prior to said sealing.
9. The method recited in claim 6 and wherein said gripped receptacle mouth is pulled and severed from the receptacle proper at said sealing line.
10. A method of packaging commodities in bags constituted of flexible material fluid-tight and fusible at least on the inner face thereof which comprises filling the bag with a selected quantity of the commodity, withdrawing gases from the bag through a nozzle to cause collapsing of the bag on the contents under the eifect of atmospheric pressure, spreading the mouth of the bag with spaced spreader members, applying collapsing pressure to a first transverse zone of the mouth portions of the bag about the nozzle and the spreaders thereby temporarily sealing the mouth of thebag about the nozzle and the spreaders so as to prevent entrance of atmosphere into the bag, withdrawing said spreaders from a second transverse zone, and applying collapsing pressure and heat to said second zone of the bag thereby hermetically sealing said bag.
11. In a machine for evacuating air from a bag containing a product to be packaged therein and for sealing the mouth of said evacuated bag containing the product, the combination of a nozzle for removing air from said bag, means for spreading the edges of the mouth of the bag about the nozzle, clamping jaws having resilient portions for pressing portions of the bag mouth on the nozzle and the spreader means and for holding closed the remairiing portions of the bag mouth, means restraining the product away from the clamping means, and means for sealing closed a spread portion of said bag.
12. The apparatus recited in claim 11 and including meansfor moving the product toward the clamping means immediately prior to sealing.
13. In a machine for evacuating air from a bag containing a product to be packaged therein and for sealing the mouth of said evacuated bag containing the product, the combination of a nozzle for removing air from said bag including a hollow tongue retractable into said nozzle and having passages therein through which to evacuate air from the bag, clamping jaws having resilient portions for pressing the bag mouth on the nozzle and for holding closed portions of the bag mouth removed from the nozzle, means for sealing closed a portion of said bag, and means for moving said hollow tongue from the portion of the bag to be sealed.
14. In the machine recited in claim 13 tensioning means for holding said product spaced from said clamping jaws and for holding the portion of the bag between the product and the jaws under tension, and means for relieving said tension prior to sealing by said sealing means.
.15. The machine recited in claim 14 and wherein surfaces of the resilient portions of the jaws which press the bag against the nozzle are stepped so that pressing surfaces of a jaw are oifset from one another.
16. The machine recited in claim 13 and including a source of high vacuum connected to the evacuating nozzle and the passages in said hollow tongue through an adjustable throttling valve.
17. The machine recited in claim 14 and wherein a resilient portion of the jaws taper to an edge of greatest resiliency.
References Cited in the file of this patent UNITED STATES PATENTS