US2826021A

US2826021A - Package forming and filling machine

Info

Publication number: US2826021A
Application number: US421352A
Authority: US
Inventors: Jacob Petrus Matheus Van Berg; Eijnden Johannes Hubertus Den
Original assignee: Package Machinery Co
Current assignee: Package Machinery Co
Priority date: 1953-04-11
Filing date: 1954-04-06
Publication date: 1958-03-11
Anticipated expiration: 1975-03-11

Description

March 11, 195s J. P. M. VAN DEN BERG ErAL 2,826,021 PACKAGE FORMING AND FILLING MACHINE '7 Sheets-Sheet 1 Filed April 6, 1954 IN V EN TORS' ...i J'. RM. Vdwaelzelg JH. Vande/lnder? .'F. P. MVAN DEN BERG ETAL PACKAGE FORMING AND FILLING MACHINE March 11, 1958 7 Sheets-Sheet 2 Filed April 6. 1954 27 21 zzV [26 VTI-flfQ .I P. M. VAN DEN BERG rs1-AL '2,826,021

PACKAGE FORMING AND FILLING MACHINE @.M, E95@ .1a. P. M. VAN DEN BERG ETAL 826,02E

PACKAGE FORMING AND FILLING MACHINE Filed April 6, 1954 '7 Sheets-Sheet 4 Avrai/mrs Marh 1l, 1958 J. P. M. VAN DEN BERG ETAL 2,826,021

PACKAGE FORMING AND FILLING MACHINE March 11, 1958 J. P. M. VANDEN BERG ETAL PACKAGE FORMING AND FILLING MACHINE Filed April e, 1954 7 Sheets-Sheet 6 March ll, 1958 J. P. M. VAN DEN BERG ETAL 2,826,021

PACKAGE FORMING AND FILLING MACHINE Filed April e, 1954 'r sheets-sheet 7 105' la! a l INVENTOIS'. PJI. Vanden er www@ United States Patent() 2,826,021 PACKAGE FORMING AND FILLING MACHINE Jacob Petrus Matheus van den Berg and Johannes Hubertus van den Eijnden, Weert, Netherlands, assignors, by mesne assignments, to Package Machinery Company, Eis; Longmeadow, Mass., a corporation of Massachuse Application April 6, 1954, Serial No. 421,352

Claims priority, application Netherlands April 11, 1953 11 Claims. (Cl. 53-51) The present invention relates to automatic packageforming and filling machines of the type wherein web packaging material is formed into a tube which is then transversely sealed at longitudinally spaced intervals and the packages are filled between successive sealing steps and severed into like packages after lling and sealing.

The web material from which the packages are formed is preferably pre-imprinted'with lettering and/or .a design successively along the web material and is fed from a roll or rolls to the packaging machine which is adjusted to form the packages with the printing and/ or design centered on each package. It will be appreciated, however, that minute variations in the machine setting from the predetermined package length will be multiplied by repeated package formation until the printing and/ or design upon the individual packages will be displaced from acceptable position. Furthermore, displacement on the individual packages of the lettering and/or design may result' from variation in the longitudinal tension upon the packaging material or from slight expansion or contraction of the web material due to variations in temperature, humidity and the like.

The present invention has for its primary object to provide in a package-forming and lling machine means which will overcome the aforementioned shortcomings in existing machines.

Further objects of the invention include: (a) to generally simplify and improve the construction of such machines so that the package length can be simply and easily varied; (b) the provision of means whereby the speed of operation of the machine can be easily changed for accommodating different articles to be packaged in relation to the size of package and the material from which the package is made; (c) the provision of improved means for varying the pressure of the heat-sealing means when using various heat-sealing web material; (d) the elimination of lost time now encountered with machines of the character set forth caused by pulling the formed package a little farther than the severing point and then pulling back the package until the centering index on the package comes abreast of the electric eye; and (e) the provision of novel transverse sealing and cut-off dies which relieve the machine of excessive wear.

l The foregoing and other objects of the invention not specifically enumerated are accomplished by the various novel means and cooperative relationship of parts of the machine, the construction and operation of which will be understood by persons skilled in the art from the accompanying drawings, when considered in connection with the following specification.

In the drawings:

Figure 1 shows a front elevation of the machine ernbodying the invention, a front plate at the base of the machine being removed to better show parts of the operative mechanism. s

Fig. 2 shows a rear elevation of the machine, a rear plate at the baseof lthe machine being removed to better illustrate certain operative elements thereof.

Mice

Fig. 3 is a vertical longitudinal section through the machine, parts thereof being shown in elevation for the sake of clarity.

Fig. 4 is an enlarged view, shown partly in section, of the tube-forming and pressure sealing die therefor.

Fig. 5 is an enlarged partial section with parts shown in elevation, of the reciprocable tube closing and pulling unit.

Fig. 6 is an enlarged elevation of the means for opening the closing and sealing clamps particularly, prior to the closing and pulling unit reaching the lower end of its downward stroke.

Fig. 6a is a section taken along the line 6a--6a of Fig. 6.

Figs. 7 to l2 show details of various parts of the machine.

Referring rst to Figs. 1 to 3 of the drawings, the machine may be said to comprise as its principal units a frame or casing A, a tube former and tube sealing means B and a reciprocable closing and pulling unit C adapted to grip, transversely seal and draw out fromthe tube former aypaekage length of web tubing at each downward stroke in the reciprocation of the unit C.

A driving shaft 1 is mounted to extend at a right angle to the front of the machine and control most of the operations of the constituent parts of the machine. The shaft 1 is driven through a chain of gears 2, 3 and 4 from a tly wheel 5, which carries a friction disc 6 which is driven by a combined cone lfriction disc and pulley 7,`

which, in turn, is driven by a V-belt 8 trained over a pulley 9 driven by an electric motor 10.

The speed at which the packages are formed and iilled may be varied in accordance with the material, size of the bag and the materials to be contained therein, and is readily accomplished by rotating a hand wheel 11 at the front of the machine, which wheel is iixedly mounted on a horizontal shaft 12 which carries a sprocket wheel 13` (Fig. 2) over which is trained a sprocket chain 14 engaging'a second sprocket wheel 15 mounted on a stub shaft 16 which is journaled in a bracket 17 and in an inner frame member 18, the other end of the shaft 16 having mounted thereon a miter gear 19 which is in mesh with a miter gear 20 secured to a screw spindle 21, which, in turn, rotates in a nut 22 connected to a sliding member 23 by bolts 24. The conical disc and pulley 7 `is also journaled in the sliding member 23, which, in turn, is movable on guides 25 and 26 which are supported by the bracket 17 and a second bracket 27 aixed to the inner frame 18. It will thus be seen that by rotating the hand wheel 11 the screw spindle 21 will be rotated in the nut 22 to shift the p cone friction disc and pulley eccentrically along the face of the friction disc 6 and hence drives said friction` disc 6 and, in turn, the ily-Wheel 5 faster or slower depending upon thedirection of rotation of the hand wheel 11.

Extending parallel to the shaft 12 on the opposite side of the machine is asecond shaft 28 to which is secured a hand wheel 29, said shaft 28 being in alignment with a shaft 28a and adapted to be coupled thereto by a spring clutch (not shown) controlled by the hand wheel. Mounted on said shaft 28a is a sprocket wheel 30 over which is trained a sprocket chain 31 which engages over a sprocket wheel 30a mounted on a stub shaft 3% (Fig. 2) which is coupled to main shaft 1 by a gear train 36C and 30d. Mounted on shaft 1 is a Vsprocket wheel 32 over which is trained a sprocket chain 32a which engages `over a sprocket wheel 32e mounted on a shaft 32h disposed between'and parallel to

shafts

12 and 28. By moving the hand wheel 29 inwardly to couple shafts 28 and 28a it will be seen that-it is possible to manually turn over the machine for making preliminary settings 'a miter gear 33 which is in mesh with a miter lgear 34 3 supported upon one end of' a vertical shaft 35 which carries at its opposite end a clutch element 36 adapted to engage a second clutch element 37 connected to a vertical shaft 38 extending through the top of the frame whereat it is adapted for Vconnection with means to control the feed of material from a reservoir (not shown) at the top of the machine for supplying the content-s of the packages to be formed and filled. A clutch-operating lever 39 mounted on a shaft 40 and passing through the clutch element 37 is adapted to control the

clutch

36, 37.

The tube former and filling device Referring now to Figs. 1, 3, 4, 8, 9, 11 and 12, the filling tube and former consists of a vertical, cylindrical tube 41 dependingly supported from the top of the machine frame and having at its lower end 'a pair of horns or spreaders 42 adapted to spread a formed tube into flattened formation after it leaves the filling tube 41 to facilitate the gripping of said tube by `the reciprocating clamp C. The package forming material 43 is fed 4around the filling tube from a reel of web material 44 supported at the top front of the machine on brackets 45. The web material, the tension upon which may be controlled in any well-known manner, is guided from the reel over rollers 46, 47 and lover former arms 48 into encircling relation about the tube 41 with the edge portions of the web in overlapping relation rearwardly of the tube 41. `Where the edge portions of the web overlap, the tube 41 is reduced in diameter 'and provided with a cushion base or rubber strip 49 to insure uniform pressure contact against the filling tube by the sealing face 50 of la pressure member 51 provided with a suitable heating element 52. The pressure member 51 is supported within a pressure member holder 53 so as to have limited reciprocal movement therein, said limited movement being provided by bolts 54 secured to the pressure member and slidable through openings in the pressure member holder. The pressure member 51 is resiliently urged into pressure sealing position by helical springs 55 mounted in sockets 56 formed in the pressure member holder 53 and for varying the tension of the springs 55 there is mounted in each of the sockets 56 a disc 57 which is backed by an adjustable screw 58 and a locking nut 59.

Reciprocating movement of the pressure member 51 into Iand out of engagement with the overlying edge portions of the web material rearwardly of the tube 41 is accomplished in the following manner: To the pressure holder member 53 is vaffixed a sliding shaft 60 which passes through a cover plate 61 secured to the machine frame. The inner end of said shaft is formed with opposite ats 62 (Fig. 12) and with a bore 63 through which extends ya shaft 64 upon which is mounted a pair of links 65 and a pair of rollers 66, which, in turn, are held on the shaft by clamping rings 67. The opposite ends of the links 65 are mounted upon a pivot pin 68 on opposite sides of one end of an arm 69 (Figs. 2 'and 3), the opposite end of which is clamped around the middle portion of a lshaft 70, one end 71 of which is journaled in a bearing '72 on the frame and the other end 73 of which is -axed to one end of an arm 74, the other end ofwhich arm engages one end 75 of a tension spring 76, the opposite end of which is anchored to a pin 77 mounted on the frame. 74 carries a transverse pin 78 which passes through an eye in the top of a guide bushing 79 which fits over the upper end of a pull rod 80. The bushing 79 has a pair of oppositely disposed ears 81 to each of which one end of a tension spring 82 is secured, the opposite ends of said springsv being secured to ears 8,3 on the pull rod 80. Carried by the lower end -of the pull` rod 80 (Fig. 1) is a fork 84 Which is pivoted to one end of a shaft 85 which carries an arm 86 secured to ya shaft 87, which, in turn, carries an arm 88 at the freel end of which is Intermediate its ends the arm a roller S9 which is held against a cam disc 90 (Fig. 3) mounted on the driving shaft 1.

When the driving shaft 1 rotates, the roller 89 is moved by the cam disc 90 so that the pull rod 80 is given a reciprocating movement up and down. At the limit of the downward movement of the pull rod the pivot 68 (Fig. 3) is in line with the centers of rotation of the

shafts

70 and 64 in which position the pressure member 51 is in tube sealing position. The tension spring 76 causes the roller 89 to remain in contact with the cam disc 90 wherefore, when the pivot 68 is displaced out of alignment with the centers of rotation of the

shafts

64 and 70 the sliding shaft 60 returns to its initial position, thus giving the pressure member 51 a reciprocating movement. As the pressure member 51 reaches its extreme right position (Figs. 3 and 4) it exerts a certain pressure on the web material so that the longitudinal seam is sealed partly by such pressure and partly under the influence of the predetermined temperature of the pressure member which is governed by the electric heating element 52. Adjustment of the pressure member is such that when it is in a contacting position with the cushion base 49, the heads of the bolts 54 are at a distance of about 1 mm. from the pressure member holder 53 so that the springs 5S determine the pressure on the seam.

In order to prevent the filling tube 41 from becoming offset or strained due to the force of the pressure member when sealing the seam, a check member 91 encompasses the lower end of the filling tube. However, said check member may not press constantly against the tube. When the pressure member 51 is moved backwardly, or to the left in Fig. 4, the check member 91 must be free of the tube 41 in order to enable the web material to slide easily along the filling tube during the downward movement of the closing and pulling clamp C. The pressure member holder 53 inthe course of its reciprocating movement to the left operates a lever system comprising a pair of parallel arms 92 which normally press against the rollers 66, the said arms being secured to a shaft 93 by the clamping screw 94, The shaft 93 is rotatably journaled in the cover 61 and has affixed at its middle an arm 95, the free end 95a of which presses against a roller 96 which is journaled on a pin 97 carried by a three-pronged bell-crank lever 98. The bell-crank is pivotally supported by a pin 99 journaled in the cover 61. The free end of the intermediate arm 98a of the bell-crank has a pin 100 aixed thereto which carries a pair of links 101, 101a (Figs. 4 and 11). The link 101 is fixed to a shaft 102 loosely extending through an opening 103 in a sliding shaft 104. The link 10111 carries a collar 10S which is fitted upon the shaft 102 and a nut 106 fixes the system 10U-105 tightly upon the sliding shaft 104. One end of a tension spring 107 is connected to the third leg 98h of the bell-crank 98 and the other end of the spring is hooked into an eye 108 secured to the cover 61. The spring 107 draws the bell-crank 98 against a stop 109 of the cover. When the bell-crank is in the position shown in Fig. 4 the fulcrurn pin 99 is in line with the pivot points and 102. The end 104er of the shaft 104 is in the shape of a clamp into which one end of a fork 110. which straddles the tube 41, is fixed by means of a locking pin 111. The fork carries the check member 91 which is adjustable on the fork by means of nuts 112. The check member 91 embraces a rubber cushion 113. In the position in which the spring 107 presses the hellcrank against the stop 109 the check member presses against the rubber cushion, which, in turn, presses against the lling tube 41. When the pressure member holder 53 moves rearwardly or to they left, the nose 95a of the arm 95 is engaged by the roller 96 and rocks the bell-crank in a clockwise direction against the tension of the spring 107 so that the sliding shaft 104, including the check member 91, is given a movement to the right. Thus the rubber cushion 113 is released from hthe web material encircling the tube 41. The effect now is that the check member 91 is already pressed on when the holder 53 is moved tothe right and at the moment when the spring pressure is exerted on the tube. Thus the tube is restrained frorn bending.

One end of the shaft protrudes outwardly from one side of the frame (Figs. l, 8 and 9) and has clamped to the end thereof a small lever 114, the free end of which ,lever in normal operation is slightly spaced apart from a longlever 115 so that the shaft 70, together with the lever 114, can move freely and independently of the lever 115. A stop 116 having an elongated recess therein formed with an intermediate shoulder 117 is affixed to the frame and through which recess the lever 115 extends so that when said lever is raised and moved over the shoulder 117, the holder 53 can be manually moved away from the tube 41. When this is done, the web material can freely be shifted along the tube in the course of setting the machine for operation. The small lever 114 in the course of this movement is engaged by the lever 115, whereupon the shaft 70 is rotated counterclockwise and,`as this is done, the guide bushing 79 is released from the end of the tension rod against the tension of springs 82. At the same time the pin 78 also moves in a counterclockwise direction, thus maintaining the roller 89 pressed against the cam disc 90 and precluding the tension rod from moving upwardly.

Clamp and pulling unit For imparting a reciprocating movement to the closing and pulling unit C there is provided a lever 118 which, at one end, is connected through a bolt 119 to a link 120 and through a pin 121 and a yoke 122 to a pair of upwardly extending shafts 123 and a downwardly extending shaft 123g. The lever 118 at its opposite end carries a pin 124 upon which is mounted a slider block 125, which, in turn, carries a roller 126 movable in a cam groove in a disc 127 mounted on the driving shaft 1. The slider block isfrectilinearly movable in

guides

128 and 129 which are connected by bolts 130 to the inner frame 18. The length of the stroke of the reciprocating pulling device is adjustable by means of a set-screw 131 in the following manner (see Figs. 3 and 10): The lever 118 has a longitudinal slot therein in which a sliding block 132 is movable and rockable about one end of a pin 133, the other end of which is slidable in a support 134 aixed within the housing. By means of the set-screw 131, the pin 133 can be shifted and locked by a nut 135 to vary the effective stroke of the end of the lever carrying the pin 119.` Each of the shafts 123 at its upper end carries a' fork 136 within which a pair of

levers

137 and 138 are pivoted at 139 and 140, respectively, which levers are biased to jaw-opening position by compression springs 140g mounted in sockets formed in the

levers

137, 138. These levers are surroundedby protective casings 141 and 142 (Fig. 5) in which sealing elements 143 and 144 containing heating elements 143:1 and 1445i are arranged. Movable between each pair of

levers

137, 138 is a Wedge 145 journaledl in a bushing 146 movable in the shaft 123. A tension rod 147 draws each wedge 145 downwardly, whereas a compression spring 149 tends to drive it upwardly. During the downward movement, the

levers

137 and 138 at their lower ends are spaced apart by

rollers

150 and 151 mounted on

pins

152 and 153, respectively, which are engaged by the wedges or cams 145. Before the wedges 145 have completed their downward stroke the

rollers

152 and 153 make an outward movement decreasing to no speed, in view of which strong forces can be produced on the clamping and sealing elements 143 and 144. Centrally of the protective casing 141 an adjusting bolt 154 abuts a blade spring 155 which is on either side supported and checked by cleats 156 (Fig. l) on the levers i137. In consequence of the pinching action of the levers4 137-and.138, the protective casing 141 recedes, putting the blade under tension. This tension Vis adjustable by means of the adjusting bolt 154. Each tension rod 147 has connected to the lower end thereof through a turnbuckle 157, a fork 158 and a pin 159 on arms 160 (Figs. l and 7). These arms are secured on a shaft 161i journaled in a support 162 carried at the lower end of shaft 123a. An arm 163 is secured to the middle of shaft 161 and carries a roller 164 which is urged by the tension rod 147 against a roller guide 165 when the sealing and pulling members C move up and down. The* roller guide 165 carries a pin 165:1 to which is pivoted at its top one end of a link 166, the opposite end of which is fixed on a pin 167 mounted in a member 168 having a bearing 169 slidable on shaft 1 and a web portion 170. The bearing 169 carries a roller follower 171 which is urged by a tension spring 172 into engagement with a cup-shaped cam 173 mounted on the shaft 1. Also fixed on the pin 167 is the intermediate point of a lever 174, one end of which lever is pivotally connected to the pin 165g and at its other end is pivoted to a pin 175a mountedy in a slidable plate 175 having a longitudinal recess 176` through which extends bolts 177 passing through a cover' plate 178 and secured to the web 170 (Fig. 6a). A second lever 179 similar to lever 174 is pivotally connected at one end to a pin 175b mounted in the slidable plate175, and at an intermediate point is xed to a pin 179a mounted in the web 170 and at its opposite end is pivoted to a pin 180. A second link 181 is fixed at one end to the pin 179g and at its opposite end is pivoted to the pin 180. The pin carries a slide block 182 which is guided in the frame and is adapted to bear against a flat surface at the opposite end of the roller guide 165. Pivotally supported on a pin 183 extending through an elongate recess 184 in the web is a bifurcated lever 185, a short arm 185:1 of which has a downwardly directed nose 186 which is biased by a spring 187 to seat in a detent 188 in the top edge of. plate 175. The opposite end of the lever is pivotally connected at 189 to a plunger rod 190 of a solenoid 191 which is adapted to be energized when an electric eye E is focused on an indexing spot S on the web. Carried by a bearing 1a for the shaft 1 (Fig. 6) is a stop shoulder 1b against which a shoulder 165e on the roller guide 165 is adapted to engage to limit the inward movement of said roller guide, as will be presently explained.

The web material 43 is adapted to be pulled down by the closing and pulling unit C until the indexing spot S on the web passes in front of the electric eye E, whereupon the sealing members 143, 144 release the tube so that further pulling thereon is impossible. After the closing and sealing dies 143, 144 have engaged the tube at the upward limit of movement of the shafts 123, downward movement of said shaft then takes place with the sealing dies gripping the tube. One of the sealing dies 143 is formed with a horizontal recess 200 therein and the other die 144 with a complemental opposed recess 201 extending therethrough. Laterally mounted in the latter recess is a cutting blade 202 carried by a shaft 203, which, in turn, is carried by a pair of levers 204 pivoted to the lever 138 on shaft 13811. The shaft 138a carries a yoke 205 which, at its middle, carries a roller 206. The roller 206 is engaged by a plunger 207 as the sealing dies move downwardly. cutting blade 202 is moved inwardly to sever the tube intermediate the seal made therein.

The plunger 207 is slidably mounted in the frame and is operable by a

toggle lever

208, 209, the arm 209 of' which, in turn, is controlled by a lever arm 210 aixed to the pull rod 80. The plunger 207 is guided in thek frame by a pin 211 slidable in a slotted arm 212. The formed and filled package when severed by the cutting blade, drops into an inclined chute 213 and is deposited in a receptacle (not shown).

In the operation of the machine the reciprocation of the sealing and pulling members C is controlled by the When such engagement "takes place thel lever 1'18 and the opening and closing of the sealing' dies 143, 144 is controlled by the movement of the roller fo1- lower 171 against the cup-shaped cam 173. When the roller 171 is at the high point of the cam 173, as shown in Fig. 3, the sealing elements 143, 144 are at the top of the pulling stroke and in clamping engagement with the web, As the sealing unit moves downwardly the roller 1-71 follows the cam 173 and, in View of the tension on the rod 147, the roller 164 is held against the guide 165. When the electric eye E is focused on the indexing spot on the web rearwardly of the package which is being pulled down by the unit C, the solenoid 191 is energized, whereupon the plunger rod 190 is raised and in doing so disengages the nose 186 from the detent 188 on the plate 175. The raising of the detent permits the plate 175 to move to the right, through the agency of

levers

174, 179, and links 166, 181, which pivot around the fixed points 167 and 179:1, as shown in Figs. 3 and 6, whereupon the roller 164 following the roller guide 16S imparts an upward movement to the wedges 145 carried by Athe tension rod, thus permitting the rollers 152 to move inwardly under the tension of the springs 140e', whereupon the clamping jaws 143 and 144 are moved outwardly to release their grip on the web tube. As this action takes place, the shoulder 165C abuts the stop 1b thus limiting the extent of movement to the left of roller guide 165. The bearing 169 and its web 170 continue to move to the left as the downward movement of the roller 164 continues until the end of the stroke, and before such end is reached, the nose 186 again engages in the detent 138. At the end of the stroke which is controlled by the cam 173, the direction of movement of the unit C is reversed and it moves upwardly to its limiting position and the roller 164 again rides upwardly. When the roller 171 again reaches the high point of the cam 173 it operates to close the jaws 143 and 144. During the downward movement of the unit the plunger 207 is activated to engage the roller 206 carried by the unit C and thereupon moves the knife 202 inwardly to sever the formed and filled package from the one next above it. The sequence of operation is repeated as long as the machine is kept operating.

From the foregoing detailed description it will be apparent that we have provided a machine which accomplishes the various objects set forth in the opening statement and, while there has been shown and described a preferred embodiment of the invention, it is to be understood that changes in details of operating parts may be made within the range of engineering and mechanical skill without departing from the spirit of the invention as claimed.

What we claim is:

l. In a packaging machine of the class described, a tube former for producing from web packaging material a tube from which sections may be transversely sealed and severed to provide a succession of packages; actuating means spaced longitudinally along such web at intervals equal to the predetermined lengths of the packages to be produced by the machine; a clamp for repeatedly engaging and pulling away from said tube former the tube produced thereby, said clamp having gripping and sealing jaws whereby the tube is gripped and transversely sealed as said clamp engages such tube and pulls it away from said tube former; means for reciprocating said clamp toward and away lfrom said tube former through an amplitude greater than the predetermined package length; means coordinated with said reciprocating means for closing the gripping and sealing jaws of said clamp at its point of reciprocation nearest said tube former; and means for opening the gripping and sealing jaws of said clamp upon reaching the end of its movement in drawingout directions; in combination with mechanism operated by said actuating means on the web for actuating said jaw opening means before full movement thereof in drawing-out directiony whereinV the gripping and sealing jaws are carried. by levers pivotally mounted on a pair of reciprocable shafts,

spring means normally bias the levers towardjaw-opening position and cam means are operable to move the levers about their pivotal mountings to open and close the jaws.

2. A packaging machine according to claim 1, wherein the cam means are operable to close the jaws against the biasing action of the springs which normally bias the jaws toward jaw-opening position.

3. A packaging machine according to claim l, wherein the cam means move with the reciprocable shafts for the major amplitude of their stroke.

4. A packaging machine according to claim 3, wherein the actuating means on the web for actuating the cam means to open the jaws is a marking on the web material and an electric eye responsive to said marking on the web material.

5. A packaging machine according to claim 3, wherein the cam means which move with the reciprocable shafts are in turn controlled by secondary cam means driven by the driving shaft of the machine and by a lever system operable by the electric eye responsive to a marking on the web material being drawn out by the sealing and pulling clamps.

6. A packaging machine wherein the web packaging material is drawn over a tube former to produce a tube, a clamp comprising a pair of coacting jaws whereby the tube produced may be gripped transversely thereof, sealed and drawn downwardly from the tube former in successive package lengths, means for moving the clamp in drawing-out direction for a distance greater than the pre determined package length and means for opening the clamp to release the tube before full movement of the clamp in drawing-out direction; each of said jaws having two spaced parallel gripping faces for coacting with complemental gripping faces on the coacting jaw to grip and transversely seal the tube along two parallel bands; a knife disposed between the parallel gripping faces in one jaw and movable between the parallel gripping faces of the complemental jaw when the jaws are closed for severing the transversely sealed tube and means for operating the knife before full movement of the clamp in the drawingout direction wherein the jaws are carried by pairs of pivotally mounted levers and the knife is pivotally supported by a corresponding lever of each pair of said levers.

7. A packaging machine according to claim 6, wherein the means for actuating the knife is a reciprocable plunger.

8. A packaging machine according to claim 6, wherein the means for actuating the knife is a reciprocable plunger mounted externally of the jaws.

9. In a packaging machine wherein web packaging material is drawn over a tubular former to produce a tube and a clamp is reciprocated to grip, seal and draw out a package length of tube, in combination, a reciprocable pressure member movable into and out of engagement with the overlapped edge portions of the web material, a check member engaging the wall of the tubular former opposed to the pressure member to prevent bending stress on said tubular former when the pressure member is pressed thereagainst and means for withdrawing the check member from engaging relation to the tubular former as the pressure member is withdrawn from its tube forming position.

l0. In a packaging machine wherein web packaging material is drawn over a tubular former to produce a tube, and a clamp is reciprocated to grip, seal and draw out a package length of tube, in combination, a reciprocable pressure member movable into and out of engagement with the overlapped edge portion of the web material, a check member engaging the wall of the tubular former opposed to the pressure member to prevent bending stress on said tubular former when the pressure member is pressed thereagainst, and a reciprocable pressure member holder and spring means biasing the pressure member for limited reciprocable movement independent of the pressure member holder.

11. A packaging machine according to claim 10, wherein spring means are mounted in the pressure member holder and press upon the pressure member, means are provided for varying such spring force and means are provided -for limiting the independent movement of the pressure member relative to the pressure member holder.

Refe'e'cs Cited in the le of this patent UNITED STATES PATENTS Vogt July 2, 1935 Hayssen Aug. 16, 1938 Smith Dec. 9, 194i Howard Apr. 28, 1953