US3629987A

US3629987A - Bag forming, filling and sealing machine

Info

Publication number: US3629987A
Application number: US40753A
Authority: US
Inventors: King L Klopfenstein; Erik O Vilen
Original assignee: Triangle Package Machinery Co
Current assignee: Triangle Package Machinery Co
Priority date: 1970-05-27
Filing date: 1970-05-27
Publication date: 1971-12-28
Anticipated expiration: 1988-12-28
Also published as: DE2126498B2; DE2126498A1; GB1289238A

Abstract

Flexible bags are formed by making spaced transverse seals along a continuous web formed by multiple layers of a heat-sealable material. The seals are made by mating sealing and cutting elements extending radially from a pair of rotary members or wheels rotating in opposite directions, to which heat is supplied by suitable means, said elements clamping the web therebetween, thus sealing and cutting and advancing the web as the members rotate. In a vertical machine the transverse seals form the bottom of one bag and the closed top of the preceding bag after it has been filled with the desired commodity. The rotary members are mounted on shafts which are displaceable toward and away from each other, thereby enabling the sealing members to move in a straight line together during the sealing operation. Means are provided for controlling the timing of the meeting and separating of the sealing elements, thereby enabling the making of bags of different lengths either automatically or by manual adjustment.

Description

United States Patent [72] Inventors King L. Klopienstein Prospect Heights;

Erik O. Vilen, Niles, both of I11. [21] App1.No. 40,753 [22] Filed May 27, 1970 [45] Patented [73] Assignee Dec. 28, 197 1 Triangle Package Machinery Company Chicago, Ill.

[54] BAG FORMING, FILLING AND SEALING Primary Examiner-Travis S. McGehee Attorney]ohnston, Root, OKeeffe, Keil, Thompson &

Shurtleff ABSTRACT: Flexible bags are formed by making spaced transverse seals along a continuous web formed by multiple layers of a heat-scalable material. The seals are made by mating sealing and cutting elements extending radially from a pair of rotary members or wheels rotating in opposite directions, to which heat is supplied by suitable means, said elements clamping the web therebetween, thus sealing and cutting and advancing the web as the members rotate. 1n a vertical machine the transverse seals form the bottom of one bag and the closed top of the preceding bag after it has been filled with the desired commodity. The rotary members are mounted on shafts which are displaceable toward and away from each other, thereby enabling the sealing members to move in a straight line together during the sealing operation. Means are provided for controlling the timing ofthe meeting and separating of the sealing elements, thereby enabling the making of bags of different lengths either automatically or by manual adjustment.

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SHEET u (If 4 If VEiu (1R5: KING L..KLOPFENSTEIN I ERIK O. VILEN ATT'YS BAG FORMING, FILLING AND SEALING MACHINE BRIEF SUMMARY OF THE INVENTION The invention relates generally to bagmaking filling and sealing machines and is more specifically directed to an improvement in the apparatus for making transverse seals in spaced relation along the length of a multiple-ply web of heatsealable material.

In bagmaking, filling and sealing machines it is customary to provide a source for a web of heat-scalable material which moves over a forming shoulder and forms the material into a tube. In some of the machines heretofore known, sealing jaws are provided which move together and clamp the tubular web therebetween. The jaws then move downwardly thereby advancing the web and simultaneously creating a seal for the top of the lower bag and the bottom of the next succeeding bag thereabove. The desired commodity is fed into the closed end tube through the open upper end thereof before such end is sealed and severed from the web. In such machines after the jaws have moved downwardly and separated, they return to their uppermost position to repeat the cycle.

In a horizontal bagmaking machine the tubular web or multiple plies in a flat condition move in a horizontal direction and seals are made transversely thereof at suitably spacedapart points. This forms the bag but the unsealed edge may form the open mouth of the bag through which the commodity may pass for filling the bag.

The matter of forming the transverse seals becomes important in considering the efficiency of the machine and the speed at which the seals are made and the web advanced. Various ways of making the transverse seals have been proposed including sealing jaws which move in an elongated closed path, either intermittently or continuously, as well as mating jaws which are mounted on continuously rotating wheels.

Problems still present themselves, however, from the standpoint of providing relatively simple adjustments whereby the length of the bags may be varied from time to time, depending upon the type and amount of commodity which it is desired to place in a given bag.

The apparatus as disclosed herein and which forms the subject matter of the present invention embodies a pair of rotating members on each of which is pivotally mounted one or more sealing elements which are caused to be brought together in mating relation, and to clamp the web therebetween. As these members continue to rotate, the shafts on which they are mounted move away from each other, while both of said members maintain the same velocity with respect to each other about their respective axes thereby causing the clamped sealing elements to move in a straight line and advance the web during the sealing thereof. Yieldable means are provided which normally urge the rotary members toward each other so that, as the sealing jaws move from their initial contact with the web to a plane passing through the centers of the members, such centers will move away from each other. As the sealing jaws then advance to the opposite side of said plane the centers on which the rotary members are mounted will move toward each other.

Suitable stop means are provided to limit movement of the rotary members toward each other, and when this limit is reached, continued rotation of the members will cause the sealing elements to separate and stop the feeding of the web. It will be evident, however, that a sufficient number of sealing elements could be provided on each rotary member so that the web could move continuously ifso desired.

The construction of the apparatus as disclosed herein lends itself not only to manual adjustment to vary the length of the bags being formed, but also to automatic control whereby means responsive to a suitable marking on the web of material will control the point at which the sealing elements will separate.

In view of the foregoing, it is the principal object of the present invention to provide a novel sealing apparatus for forming transverse seals in a multiple-ply web fed through a bag forming, filling and sealing machine, and which is designed to overcome the disadvantages of similar bag machines heretofore known.

A further object of the invention is to provide a novel apparatus for transversely sealing a multiple-ply web of a heatsealable material at spaced-apart points along the length thereof wherein the distance between such transverse seals may be changed either automatically or manually, thereby changing the length of the bag being formed.

Another object of the invention is to provide apparatus for forming a plurality of spaced-apart transverse seals along the length of a multiple-ply web of heat-scalable material wherein a plurality of sealing members are mounted on rotating elements which rotate in opposite directions, thereby bringing pairs of mating sealing elements together and clamping the web therebetween to seal and advance the material through a predetermined distance, and wherein said rotating members are mounted on shafts which are displaceable toward and away from each other.

A still further object of the invention is to provide a bag forming, filling and sealing machine with novel means for transversely sealing the multiple-ply web of heat-sealable material at spaced-apart points along the length thereof, wherein the size of the bags being made is controlled by varying the timing when the sealing jaws grip and release the web either automatically or by manual adjustment,

Other objects and advantages of the invention will become apparent upon reading the following description taken in conjunction with the accompanying drawings, in which:

FIG. I is a front elevational view of a machine embodying a preferred form of the present invention showing a pair of the rotary sealing elements initially clamping the web of multipleply heat-scalable material therebetween;

FIG. 2 is a view similar to FIG. I but illustrating the same pair of mated sealing elements at the point in their movement when the centers of the rotary members are farthest apart, and wherein the sealing elements are in the same plane as the plane passing through the centers of the rotary members;

FIG. 3 is a top plan view of the machine shown in FIGS. I and 2 but with the forming shoulder and filling tube omitted therefrom;

FIG. 4 is an enlarged fragmentary vertical sectional view of a part of the machine taken substantially along the plane of line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary horizontal sectional view partly in elevation and taken substantially along the plane of line 5-5 ofFIG. 1;

FIG. 6 is a fragmentary enlarged vertical sectional view taken substantially along the plane of line 6-6 of FIG. 3 with parts thereof being shown in elevation;

FIGS. 7, 8, 9 and 10 are somewhat diagrammatic views showing the various positions of mating sealing elements in the formation of a bag from initial contact with the web to the point where they separate merely by continued rotation of the rotary members;

FIGS. II, I2, 13 and I4 are somewhat diagrammatic illustrations of the path of movement of mating sealing elements but utilizing the automatic control for regulating the length of bag being formed, wherein the mated sealing elements are caused to separate automatically before they normally would separate merely due to continued rotation of the rotary members, thereby making a bag which is shorter than that shown in FIGS. 710; and

FIG. 15 illustrates an alternative form of sealing element, wherein the outer ends thereof are arcuate instead of flat.

DETAILED DESCRIPTION Referring now more particularly to the drawings, and especially to FIGS. 1, 2 and 3, the apparatus embodying the present invention has been disclosed, for purposes of illustration, as including a frame consisting of uprights l and 2 at the front and rear of the frame, upper front and rear

cross supporting members

3 and 4, and the horizontal side supports 5 and 6. At the front of the machine an additional horizontal crossmember 7 is provided for supporting the front ends of a pair of shafts, as will be pointed out more particularly hereinafter.

A crossmember 8 is provided near the bottom of the frame which provides a support for the air and hydraulic cylinder assembly used for regulating the length of bag, also as more particularly pointed out hereinafter.

Bagmaking machines of the general type to which the present apparatus pertains may be of either a vertical type or a horizontal type. For purposes of illustration, the machine shown herein is of the vertical type wherein a web W of a suitable heat-scalable material is caused to pass through a circuitous path from a suitable source, such as a roll, to a forming shoulder 9. As the web passes over the shoulder it is formed into a tubular shape around a filling tube I0. Normally, in such a vertical machine, a sealer element 11 is caused to move into contact with the overlapping longitudinal edges of the web to perform a longitudinal seal and complete the formation of the tubular length of heat-sealable material. Transverse seals are then formed in spaced relation along the length of the tubular web, which seals form the bottom of a bag to be filled and closes the top of a bag which has been filled. This is all in accordance with customary and well-known practices familiar to those skilled in this art.

In a horizontal bagmaking machine the web may either be folded as it enters the machine or it may have been previously folded to form a multiple-ply web, and the vertical transverse seals to form the bag are applied in spaced-apart relation. Usually in the horizontal machines the bags are first formed and then filled at a later station, after which the open upper end is closed and heat sealed.

It is to be understood, of course, that as far as the present invention is concerned the web being fed to the horizontal transverse sealing elements may have been previously formed into a multiple-ply web instead of passing over a forming shoulder to form a tube. Also the bag may be filled and sealed in the manner herein shown, or merely transversely sealed with the longitudinal seal omitted until some time later after filling.

As mentioned heretofore, transverse sealers have been used wherein sealing jaws grip the web at an upper point and then draw the web downwardly, after which time the jaws separate and return in a substantially linear movement to their uppermost position.

Another form of transverse sealer may include the rotary type wherein one or more pairs of sealing jaws on opposed sides of the web move in a closed path. Such closed path may be of an elongated form such as that shown in Hoellzer et al. U.S. Pat. No. 2,962,843 or the carrier for the sealing elements may be circular and rotate continuously in a manner, for example, like that shown in the Vreeland et al. U.S. Pat. No. 3,212,229.

In this latter type of sealing apparatus it has been customary to mount the sealing jaws on their rotating carrier in such a way that the jaws will move in a substantially radial direction with respect to the rotary member during the sealing of the web.

A novel feature of the present invention is the use of rotary members which are pivoted or otherwise mounted for displacement toward and away from each other, during the sealing cycle while each pair of sealing elements is mated with the web clamped therebetween.

In the form of the invention as illustrated herein, there is provided two rotary members generally indicated by the numerals l2 and 13, respectively. These rotary members may comprise either wheels on which the sealing elements are mounted or may be in the form of spiders as shown. The rotary member 12 is mounted for rotation on a shaft 14 extending from front to rear of the frame and suitably mounted in bearings within a sleeve 15. The other rotary member 13 is similarly mounted on a rotary shaft 16 mounted in the bearings 17 within-the sleeve 18.

Each of the rotary members I2 and I3 is provided with a plurality of sealing elements or jaws to which heat is applied by suitable means well known to those skilled in the art. The number of such elements may vary from one on each member to several, depending upon the length of the bag to be made, the speed at which the members are to rotate, and whether or not it is desired to move the web intermittently or continuously. Obviously, the greater the number of sealing elements for a given diameter of the rotary member the shorter will be the bags and the space between the transverse seals. If the number of sealing elements is sufficiently large so that one pair come together to clamp the web therebetween and advance it before the preceding pair has separated and stopped movement of the web, then the web will move continuously.

In the present illustration the rotary member 12 is shown as being provided with three radially extending

arms

19, 20 and 21. The rotary member 13 is likewise provided with the same number of radially extending

arms

22, 23 and 24. At the end of each of these arms there is provided a jaw or sealing element and when they are rotated, opposed elements come together in mating pairs to form a transverse seal and to advance the web of material.

The sealing elements for the rotary member 12 mounted at the outer ends of the radial arms are indicated by the

numerals

25, 26 and 27 while the comparable elements for the rotary member 13 are indicated by the

numerals

28, 29 and 30.

Each element is shown in FIGS. 1, 2 and 7 through 14 as having a flat face and as pivotally mounted on its associated arm, and each is normally and yieldably maintained in a position so that it forms a continuation or radial extension of its associated arm by means of a pair of springs, such as indicated in each instance by the numeral 31.

The flat face portions of each sealing element come together in mating pair relation with the web therebetween and with the faces thereof flat against each other. Each of the sealing elements on the rotary member 12 is provided with a slot 32, and each of the elements on the rotary member 13 is provided with a knife 33. When the faces of the mating elements come together such as the

elements

27 and 30 in FIGS. 1, and 7 through I4, the top ofa filled bag B and the bottom of the next succeeding bag is formed by the transverse seal, and the knife 33 thereof is caused to move into the slot 32 of its mating element and sever the web at that point. It will be evident that other means for severing the web than the knife may be used if desired.

As the shafts l4 and 16 rotate in opposite directions they will carry with them the rotary members I2 and 13, and the sealing elements thereon, to a point where a pair of sealing

elements

27 and 30 will come together and clamp the web therebetween. The pivots for these specific sealing elements are indicated by the

numerals

34 and 35. Each sealing element is likewise provided with a pair of rollers, such as those which may be seen at 36 and 37, which are adapted to cooperate with vertically extending guide bars 38 and 39 positioned in the path of movement of such sealing elements to orient the faces thereof in substantially parallel relation before they meet.

It is advisable for the most efficient operation of the ap paratus that the flat faces of opposed sealing elements come together against the web in substantially parallel relation rather than having the edges thereof meet first and then come together in a rolling motion. Thus, as the arms rotate toward each other and the rollers on the respective sealing elements come against the guide bars 38 and 39 the elements are caused to rotate and move the faces of opposed pairs into parallel relation so that they will move and come together in the positions thereof shown in FIG. 1.

As the rotary members continue to rotate and move the arms and the mating sealing elements from the positions thereof shown in FIG. 1, such elements will move downwardly in a straight line. In order to permit this straight line movement of the sealing elements the shafts l4 and 16, on which they are mounted, will be caused to move or be displaced away from each other to the positions thereof shown in FIG. 2. It will be noted in FIG. 2 that in this position a horizontal plane through the center of the mating sealing elements will also pass through the centers of the

shafts

14 and 16. At this point these shafts will be at their greatest distance apart. As the rotary members and arms continue to rotate and the mating sealing elements continue to move downwardly and draw the web therewith, the

shafts

14 and 16 will move or be displaced back toward each other until they are stopped and the mating elements separate or until such inward movement of the shafts is otherwise caused to stop in a manner hereinafter described.

As will presently be seen, these

shafts

14 and 16 are mounted for displacement about a pivot point and, therefore, their centers move in an arcuate path. The horizontal plane through those shafts, which also passes through the mated sealing elements, will be at that point when the shafts are farthest apart. Other mounting means could be provided if desired, which would cause displacement of the shafts in a straight line.

The

shafts

14 and 16 are mounted for arcuate displacement toward and away from each other about the

shafts

40 and 41 as pivots which have the

sleeves

42 and 43 thereon, respectively. The

shafts

40 and 41 are mounted for rotation in suitable bearings 44 at the front of the frame in the supporting cross members 7 (see FIG. 4). Both shafts are mounted so that they may rotate about their own centers and so that the

sleeves

42 and 43 around these shafts may oscillate around the same centers.

The sleeve on shaft 14 is connected with sleeve 42 on shaft 40 by means of a plurality of

arms

45, 46 and 47. The sleeve 18 on shaft 16 is connected to sleeve 43 on shaft 41 by means of a similar plurality of connecting

arms

48, 49 and 50 (see FIGS. 3 and 4). The two sleeves l5 and 42 are likewise connected by a plate 51 at the rear end thereof while a similar plate 52 connects the

sleeves

18 and 43. These are specially formed connecting arms or plates and are shaped as to be able to support idler gears as will become more apparent hereinafter.

Intermediate the ends of the various shafts, above mentioned, a pair of

lever arms

53 and 54 are secured at one end thereof to the sleeve 43 and extend inwardly therefrom (see FIGS. 3, 4 and 5). At their other ends these lever arms are pivotally connected to the

respective links

55 and 56. The lower end of each

link

55 and 56 is pivotally connected by means of suitable pivot pins to the outer ends of an adapter member 57.

Similarly, at the other side of the frame a pair of

lever arms

58 and 59 are connected at one end thereof to the sleeve 42 and extend inwardly therefrom. The opposite end of each

lever arm

58 and 59 is pivotally secured to the

respective links

60 and 61. The lower end of each of these last-named links is also connected by suitable pivot pins to the same adapter member 57.

Thus far, it will be evident that movement away from each other, of the two

shafts

14 and 16, together with their

respective sleeves

15 and 18, will cause rotation of the respective

lower sleeves

42 and 43 in a manner such as to raise the ends of the

lever arms

53, 54, 58 and 59 upwardly, carrying with them the

respective links

55,56, 60 and 61. Movement of the

shafts

14 and 16 toward each other will likewise cause the aforesaid links to move downwardly. Conversely, upward movement of the links will cause the

shafts

14 and 16 to be displaced away from each other and downward movement thereof will cause said shafts to move toward each other.

It is evident that movement of the adapter 57 and the lower ends of

links

55, 56, 60 and 61 should be stabilized and move in a straight line to avoid side thrust and to insure equal pressures being exerted by both of the mating sealing elements. This may be accomplished in several different ways either by providing guideways for the adapter 57 or by maintaining rigid the remainder of the assembly with which the adapter is associated, as will appear more fully hereinafter.

The driving mechanism which causes rotation of the

shafts

14 and 16, and the

rotary members

12 and 13 mounted thereon, includes a drive motor M having an output shaft 62 on which is mounted a sprocket 63. The sprocket chain 64 passes around the sprocket 63 and a second sprocket 65 on shaft 66 suitablyjournaled in a support 67.

The opposite end of shaft 66 has a sprocket wheel 68 mounted thereon and is caused to rotate by rotation of shaft 66 through the aforesaid drive from the motor (see FIG. 3). A sprocket chain 69 (FIGS. 1 and 2) passes around the sprocket 68 at the upper part of the frame, then around a sprocket wheel 70 on shaft 71 mounted for rotation in a bracket 72, around the large sprocket wheel 73, and a second large sprocket wheel 74, in a manner to rotate these last named sprockets in opposite directions.

The aforesaid drive causes rotation of the

shafts

40 and 41 and, by means of a suitable gear train, also rotates the

shafts

14 and 16, with the

rotary members

12 and 13 thereon, in opposite directions to each other. To accomplish this, shaft 41 has mounted thereon a gear 75 which meshes with an idler 76 mounted for rotation on a stub shaft 77 on the rearmost connecting arm or plate 52 (see FIGS. 4 and 6). This idler meshes with gear 78 on shaft 16 thereby rotating that shaft and the rotary member 13 thereon in a counterclockwise direction as viewed in FIGS. 1 and 2.

A similar arrangement is provided on the opposite side of the frame wherein a gate 79 is mounted on the shaft 40 and meshes with the idler gear 80. This, in turn, meshes with the gear 81 on shaft 14, thereby rotating it and the rotary member 12 thereon in a clockwise direction.

Thus it will be seen that the drive as above described will impart a continuous rotation of the

rotary members

12 and 13 in opposite directions, and that the direction of rotation of the rotary members and the rotational velocity thereof will be the same as the direction of rotation and rotational velocity of the driven

shafts

40 and 41 associated with each said member. This rotational velocity of the rotary members is not altered by movement thereof toward and away from each other due to the action of the mated sealing elements. Each time a pair of opposed sealing elements meet and clamp the web of material therebetween the web will be sealed, severed and drawn downwardly in a straight line from the position shown in FIG. 1 until the elements have moved to a point which is substantially the same distance on the opposite side of a plane passing through the centers of the

shafts

14 and 16. During this time these aforesaid shafts l4 and 16 will be forced to move away from each other and then back toward each other until they encounter suitable stop means. Continued rotation of the rotary members will then cause the sealing elements to separate and the next pair of elements will be brought together to perform another cycle. As previously mentioned, each of the rotary members may be provided with only one sealing element in which case the pairs would meet only every 360 of rotation. Additional sealing elements on each member would cause successive pairs to meet more often and form a greater number of bags for the same speed of rotation of the members.

Yieldable means are provided to urge the

shafts

14 and 16 toward each other, and it will be evident that during the first part of the movement of the mated sealing elements these shafts will move apart against the force of the yieldable means, but such force will act to move the shafts toward each other and maintain the sealing elements in contact with the web until a suitable stop means is encountered.

Such yieldable means may take any suitable form, either mechanical or compressible fluid under pressure. For purposes of illustration there is shown herein a cylinder having a piston therein which is urged by fluid pressure, for example, air, in a suitable direction to urge the rotary members toward each other. The piston rod thereof is connected to the associated linkage and movement downwardly of the rod under urging of the fluid pressure will act to urge the shafts and rotary members together. More specifically, as may be seen in FIGS. 1 and 2, there is provided an air cylinder 82 having a piston 83 therein connected with a piston rod 84 which extends upwardly through the closed top of the cylinder. The upper end of the piston rod 84 is secured to the adapter plate 57 at the center thereof. An air line 85 is provided through which air under pressure may be admitted to the upper end of the cylinder 82.

' It will thus be evident at this point that the air under pressure will normally urge the piston 83 and its rod 84 downwardly. Since the piston rod 84 is connected to the adapter 57, to which the

links

55, 56, 60 and 61 are also connected, the air pressure will urge those links and the members connected thereto downwardly. It will be evident that this force through the

lever arms

53, 54, 58 and 59, and the

arms

48, 49, 50 and 52 on the one side, and the

arms

45, 46, 4'7 and 51 on the other side will cause the two shafts l4 and 16 and the rotary members mounted thereon to be constantly urged toward each other.

When the adapter plate 57 comes against the closure at the upper end of cylinder 82, it will form a stop which prevents the shafts l4 and 16 and the

rotary members

12 and 13 from mov ing any closer together. It is in this way that the length of the bag being made is controlled.

For example, let us assume that when the mating sealing elements first clamp the web in the position shown in FIG. 1 they will move downwardly 4 inches to the halfway point as shown in FIG. 2 where a horizontal plane through the center of the sealing elements will also pass through the centers of the shafts l4 and 16. It will be noted at this point that the adapter 57 and piston 83 will have been elevated to its highest position and the two shafts will be at their greatest distance apart. Taking this same example, the adapter 57 will have moved upwardly from the closed upper end of the cylinder 82, a distance in proportion to the distance through which the sealing elements have travelled.

Continued rotation of the rotary members and movement of the sealing elements downwardly will occur until the adapter 57 comes against the upper closure of the cylinder 82 at which time the sealing elements will have moved down another 4 inches, making an 8-inch bag. At this point the movement of the rotary members toward each other will stop and continued rotation thereof will cause a separation of the sealing elements as shown, for example, in FIG. 10.

If it is desired to make only the same size bag at all times, no adjustment would be necessary and fixed stops could be provided to limit inward movement of the rotary members the desired amount and the yieldable means could be merely a tension spring pulling downwardly on the linkage arrangement. In most uses of such a machine, however, it will be highly desirable to be able to make bags of different lengths, and for this reason both manual and automatic control of the bag length has been provided.

If it is assumed that the stroke of the piston rod 84 in FIGS. 1 and 2 is at its maximum, then the length of the bag being made will be the maximum length which can be made on this particular machine. It will be evident, then, that if the stroke of the piston rod 84 is made shorter the two mated sealing elements will arrive at clamping position later than normal and will be caused to separate sooner than normal, thereby shortening the length of the bag.

In the particular embodiment of the invention disclosed herein the stroke of the piston rod 84, and consequently the distance through which the adapter 57 moves during a given cycle, is determined by adjusting the position of the cylinder upwardly or downwardly in an axial direction.

As will be seen presently, there is also provided an arrangement which operates automatically to. stop inward movement of the rotary members and thereby control the size of the bags. This latter control involves a second cylinder 86 which is either mounted in tandem with the cylinder 82 or which is a continuation thereof with a suitable wall dividing the two cylinders. The cylinder 86 will have hydraulic fluid therein whereas the cylinder 82 is provided with air pressure, and suitable seals are provided to keep the two fluids separated.

Cylinder 86 has a piston 87 therein which is mounted on the same piston rod 84 on which the piston 83 is mounted. A hydraulic fluid conduit 88 is connected to a suitable port in the cylinder 86 at the top thereof while conduit 89 is likewise connected to a suitable port in the lower end of cylinder 86, and the two conduits are connected by a third conduit 90 in which there is located a valve 91.

Any suitable construction of valve may be used so that when the valve is open and the piston 87 moves upwardly while a bag is being formed, hydraulic fluid will flow outwardly through conduit 88 and the valve and then back to the cylinder below the piston through conduit 89. The reverse action will take place during the last half of the bag-forming operation while the sealing elements move from their position in FIG. 2 downwardly to the point where they separate. As may be presently seen, if the valve 91 is closed to prevent flow of fluid therethrough, or if it is restricted, thereby to restrict the flow of fluid therethrough it will act in a similar manner to the aforesaid stop means to control the length of the bag being formed.

One of the important advantages of the present invention is the ability to control the length of bag being made either manually or automatically. The manual control will be discussed first.

As was mentioned above, it may be assumed that the cylinder 82 and the cylinder 86 are in their lowermost position wherein the maximum length of bag will be made. If it is desired to manually adjust the apparatus for making shorter bags this may be done by moving the air cylinder 82 upwardly. It will be noted that a lug 92 extends downwardly from the lower end of the cylinder 86. An adjusting stud 93 is threadedly connected at its upper end to the lug 92 and passes downwardly through the crossmember 8. Locking

nuts

94 and 95 engage the threaded stud 93 to lock the assembly in any position to which it may be adjusted. As mentioned hereto fore, the cylinders may be held rigid by suitable means (not shown) to insure a straight line movement of the adapter 57.

For producing a shorter bag the threaded stud 93 is adjusted to move the cylinder assembly upwardly. This adjustment will also move upwardly the adapter 57, the

links

55, 56,60 and 61, and the

lever arms

53, 54, 58 and 59 to which those links are pivotally connected. By reason of the arrangement heretofore described, this will rotate the

sleeves

42 and 43 in a direction to move the shafts l4 and 16 farther apart and will carry with them the

rotary members

12 and 13 on which the sealing elements are mounted.

During the operating cycle the uppermost position of the adapter 57 will always be the same as illustrated in FIG. 2 which moves the

shafts

14 and 16 to their positions at which they are the greatest distance apart. With the cylinder assembly in a higher position, however, the stroke of the piston rod and the distance through which the elements connected therewith will be shorter.

If the downward movement of the piston rod is stopped at a point higher than that shown in FIG. 1 (by reason of the elevation of the cylinder assembly) then the minimum distance between the

shafts

14 and 16 in a given cycle will be greater than that shown in FIG. 1. The result of this arrangement then is that opposed pairs of sealing elements will come together and grip the web later in their cycle of rotation and at a lower point than that shown in FIG. 1. It likewise follows that after the sealing elements have passed their midpoint as shown in FIG. 2 in their downward movement, the movement of the two shafts toward each other will be stopped sooner than normal, and thus the two sealing elements will be separated and move away from each other earlier in their rotative cycle. It follows, therefore, that the length of the bag will be shorter in proportion to the distance through which the cylinder assembly is moved upwardly. This may also be illustrated by reference to FIGS. 7 through 10. FIG. 7 shows the mating of the sealing elements initially for a given setting of the stop means. FIGS. 8 and 9 show successive positions of the elements as they move downwardly, and FIG. 8 shows the knife 33 ofone element entering the slot 32 of the opposed element for severing the lower formed bag from the web. FIG. 10 illustrates the fact that when the movement of the shafts l4 and 16 toward each other is stopped, continued rotation of the sealing elements will cause the lowermost ones to separate, thereby releasing the formed bag B and the formed web, which, in the embodiment shown, will then stop movement until the next succeeding pair of elements and 28 come together and clamp the web. Since these views are diagrammatic, no stop means has been shown but it will be evident that such stop means must be provided to limit inward movement of the axes of the rotating members toward each other. Adjustment of the abovedescribed stop means will cause the mated sealing elements to come together later or earlier and cause them to separate earlier or later, and thereby control the length of the bag being formed.

It will be evident that other specific forms of stop means may be utilized to control the minimum distance between the axes of the

rotary members

12 and 13 than that shown herein, and it will likewise be evident that if it is desired to have only a manual control the hydraulic cylinder may be dispensed with. The purpose of having the two types of controls is that in some instances the web of wrapping material will be plain and unprinted and a manual adjustment will be sufficient. Where the web of material has printing thereon, it is more difficult to adjust the stopping point of the inward movement of the shafts on which the rotary members are mounted to obtain accurate registration. When the film is imprinted it is preferable to have automatic control for the registration and length of bags to insure that the bag length will be proper and that the printing will appear at the desired place on every bag.

Having thus described the manner in which the manual control for bag length operates, we may now consider the automatic control where the web of wrapping film has registration markings thereon at predetermined spaced-apart intervals to which an automatic control responds, thereby stopping movement of the axes of the rotary members toward each other.

For this purpose there is provided an electric eye, or other similar type of photoelectric responsive means, generally indicated by the numeral 96, which is positioned at a predetermined location adjacent the moving web of film, so that it will detect the presence of a particular registration marking thereon.

As illustrated, when a given registration marking is detected by the electric eye it responds through suitable circuitry to close or partially close the valve 91. This will stop or restrict the flow of fluid out of the cylinder 86 and will stop or slow the downward movement of the piston rod 84 and all of the various elements and linkages connected thereto. This will result in a stopping, or at least a retarding of the movement of the axes of the rotary members toward each other long enough for the continued rotation thereof to cause the mated sealing elements to separate. This action is of a very short duration and merely causes separation of the sealing elements long enough to release the bag B which hasjust been completed as well as the lower end of the next succeeding bag.

This action may be understood by reference to FIGS. 11 through 14. It is assumed that the rotation of the sealing elements will cause them to come together initially as in FIG. 7, and that the severing action will take place as in FIG. 8. Continued rotation will then bring the web and sealing elements downwardly as in FIG, 11. At a suitable predetermined point in this travel, the registration marking on the web will be detected by the electric eye which will respond thereto as described above and close or restrict the valve opening, thereby stopping or restricting the flow of fluid out of the hydraulic cylinder 86. At this point the axes of the rotary members will either stop their movement toward each other or such movement will be retarded a sufficient amount to cause the mated sealing elements to separate by continued rotation of the rotary members. This point in the cycle is illustrated in FIG. 12.

Since this action is only of sufficient duration to release the formed bag and the web, the valve 91 will again open permitting flow of fluid and continued movement of the axes of the rotary members toward each other, and the mated sealing elements will again come together but without any web therebetween as shown in FIG. 13. From that point on the normal sequence will take place and the sealing elements will separate in the normal course of rotation of the rotary members.

FIG. 15 illustrates a modified form of sealing element construction wherein the outer end of each of the arms on the rotary members is arcuate so that mating pairs may move together in rolling contact with the web. Such arcuate surfaces are indicated by the numeral 97 on the ends of arms 19', 20' and 21 of wheel 12', and by the numeral 98 on the ends of

arms

22, 23' and 24 of wheel 13'. It will be noted that when such arcuate mating surfaces are utilized, the pivotal mounting of the sealing elements on their respective arms may be eliminated, as well as the guide bars 38 and 39.

From the foregoing description it will be evident that we have provided a novel apparatus for sealing and severing bags formed from a web of a heat-scalable material. As indicated heretofore, the arrangement by which the axes of the rotary members may be displaced toward and away from each other during the bag-forming operation enables both manual and automatic control of the length of the bags being formed. It may also be reiterated here that the direction and rotational velocity of the rotary members is the same as the direction and rotational velocity of the

drive shafts

40 and 41. By means of this drive the mated sealing elements will always move together at the same rate and will prevent either one of the elements creeping ahead of the other despite the movement of the rotary elements toward and away from each other due to the action of the matingjaws.

Changes may be made in the form, construction and arrangement of parts from those disclosed herein without in any way departing from the spirit of the invention or sacrificing any of the attendant advantages thereof, provided, however, that such changes fall within the scope of the claims appended hereto.

The invention is hereby claimed as follows:

1. Apparatus for making spaced transverse seals along a length of a multiple-ply web of heat-sealable material to form bags, and for advancing said web, comprising, a pair of spaced shafts, means mounting said shafts for displacement toward and away from each other, a rotary member mounted on each of said shafts, means for rotating said rotary members in opposite directions, at least one sealing element mounted on each of said rotary members and so arranged that rotation of said rotary members in opposite directions will cause the faces of an opposed pair of sealing elements to come together in mating relation on one side of a plane passing through said shafts and clamp the web therebetween, sealing the web and advancing it during said rotation while said sealing elements move to a predetermined point at the other side of said plane, yieldable means for urging said shafts and rotary members toward each other, thereby creating pressure between said mated sealing elements, said shafts and rotary members being displaced away from each other during movement of said mated sealing elements from initial contact with the web to said plane and then toward each other until said mated sealing elements reach a predetermined position at the other side of said plane,

2. The combination of elements defined in claim 1, wherein each sealing element has a substantially flat face thereon and is pivotally mounted on its associated rotary member.

3. The combination of elements defined in claim 1, wherein the face of each of said sealing elements is arcuate.

4. The combination of elements defined in claim I and means to vary the spacing between said transverse seals, thereby to change the length of the bags being formed.

5. The combination of elements defined in claim 1 and manually operable means adjustable to vary the spacing ,A between said transverse seals, thereby changing the length of the bags being formed.

6. The combination of elements defined in claim 1, including stop means to limit movement of said shafts and rotary members toward each other, and means to adjust the position of said stop means, thereby to control the minimum distance between said shafts during a given cycle, and regulating the length of the bags being formed.

7. The combination of elements defined in claim 1, and means to control automatically the spacing between said transverse seals and the length of bags being formed, including means responsive to a marking on the web to interfere with or interrupt the movement of said shafts toward each other, whereby said mated sealing elements will separate during'continued rotation thereof and stop advancement of the web.

8. The combination of elements defined in claim 1, wherein said yieldable means includes a compressible fluid under pressure.

9. The combination of elements defined in claim 1, wherein said means for mounting said shafts for displacement includes a pivot means for each said shaft, an arm connecting each said shaft with its associated pivot means, whereby displacement of said shafts will be in an arcuate path about each of said pivot means, and connecting means between each of said pivot means and said yieldable means whereby displacement of said shafts will rotate said pivot means and said connecting means, and rotation of said pivot means by movement of said connecting means will cause displacement of said shafts,

10. The combination of elements defined in claim 9, including stop means to limit movement of said shafts and rotary members toward each other, and means to adjust the position of said stop means, thereby to control the minimum distance between said shafts during a given cycle and regulating the length of the bags being formed.

11. Apparatus for making spaced transverse seals along the length of a multiple-ply web of heat-scalable material to form bags, and for advancing said web, comprising, a pair of rotary members, means mounting said members for rotation on centers which are displaceable toward and away from each other, means for rotating said members in opposite directions, at least one sealing element mounted on each of said rotary members and so arranged that rotation of said rotary members in opposite directions will cause the faces of an opposed pair of sealing elements to come together in mating relation on one side of a plane passing through said centers and clamp the web therebetween, sealing the web and advancing it in a substantially straight line during said rotation while said sealing elements move to a predetermined position at the other side of said plane and separate, said members moving away from each other during movement of said mated sealing elements from initial clamping position to said plane, and toward each other after said elements pass said plane, yieldable means normally urging said rotary members toward each other, and means to vary the position at said other side of said plane where said sealing elements separate, thereby controlling the distance between the transverse seals and the length of the bags being formed.

12. The combination of elements defined in claim 11, and means operable to position the faces of said opposed pair of sealing elements in substantially parallel relation prior to clamping the web therebetween,

13. The combination of elements defined in claim 11, wherein said last-named means includes a control device operable to interfere with or interrupt movement of said rotary members toward each other.

14. The combination of elements defined in claim 11, wherein said last-named means includes a manually adjustable control device operable to stop movement of said rotary members toward each other.

15. The combination of elements defined in claim ll, wherein said last-named means includes a pair of chambers in closed communication with each other and containing a substantially fixed volume of a suitable fluid, means for varyln the capacity of each said chamber in response to movement 0 said rotary members toward and away from each other, whereby fluid will be displaced from one chamber to another in one direction when said rotary members move toward each other, and fluid will be displaced from said other chamber to said one chamber in the opposite direction when said members move away from each other, and means responsive to a marking on the web to control the displacement of the fluid in said one direction, thereby interfering with or interrupting movement of said rotary members and causing said sealing elements to separate.

Claims

1. Apparatus for making spaced transverse seals along a length of a multiple-ply web of heat-sealable material to form bags, and for advancing said web, comprising, a pair of spaced shafts, means mounting said shafts for displacement toward and away from each other, a rotary member mounted on each of said shafts, means for rotating said rotary members in opposite directions, at least one sealing element mounted on each of said rotary members and so arranged that rotation of said rotary members in opposite directions will cause the faces of an opposed pair of sealing elements to come together in mating relation on one side of a plane passing through said shafts and clamp the web therebetween, sealing the web and advancing it during said rotation while said sealing elements move to a predetermined point at the other side of said plane, yieldable means for urging said shafts and rotary members toward each other, thereby creating pressure between said mated sealing elements, said shafts and rotary members being displaced away from each other during movement of said mated sealing elements from initial contact with the web to said plane and then toward each other until said mated sealing elements reach a predetermined position at the other side of said plane.

4. The combination of elements defined in claim 1 and means to vary the spacing between said transverse seals, thereby to change the length of the bags being formed.

5. The combination of elements defined in claim 1 and manually operable means adjustable to vary the spacing between said transverse seals, thereby changing the length of the bags being formed.

7. The combination of elements defined in claim 1, and means to control automatically the spacing between said transverse seals and the length of bags being formed, including means responsive to a marking on the web to interfere with or interrupt the movement of said shafts toward each other, whereby said mated sealing elements will separate during continued rotation thereof and stop advancement of the web.

9. The combination of elements defined in claim 1, wherein said means for mounting said shafts for displacement includes a pivot means for each said shaft, an arm connecting each said shaft with its associated pivot means, whereby displacement of said shafts will be in an arcuate path about each of said pivot means, and connecting means between each of said pivot means and said yieldable means whereby displacement of said shafts will rotate said pivot means and said connecting means, and rotation of said pivot means by movement of said connecting means will cause displacement of said shafts.

11. Apparatus for making spaced transverse seals along the length of a multiple-ply web of heat-sealable material to form bags, and for advancing said web, comprising, a pair of rotary members, means mounting said members for rotation on centers which are displaceable toward and away from each other, means for rotating said members in opposite directions, at least one sealing element mounted on each of said rotary members and so arranged that rotation of said rotary members in opposite directions will cause the faces of an opposed pair of sealing elements to come together in mating relation on one side of a plane passing through said centers and clamp the web therebetween, sealing the web and advancing it in a substantially straight line during said rotation while said sealing elements move to a predetermined position at the other side of said plane and separate, said members moving away from each other during movement of said mated sealing elements from initial clamping position to said plane, and toward each other after said elements pass said plane, yieldable means normally urging said rotary members toward each other, and means to vary the position at said other side of said plane where said sealing elements separate, thereby controlling the distance between the transverse seals and the length of the bags being formed.

12. The combination of elements defined in claim 11, and means operable to position the faces of said opposed pair of sealing elements in substantially parallel relation prior to clamping the web therebetween.

15. The combination of elements defined in claim 11, wherein said last-named means includes a pair of chambers in closed communication with each other and containing a substantially fixed volume of a suitable fluid, means for varying the capacity of each said chamber in response to movement of said rotary members toward and away from each other, whereby fluid will be displaced from one chamber to another in one direction when said rotary members move toward each other, and fluid will be displaced from said other chamber to said one chamber in the opposite direction when said members move away from each other, and means responsive to a marking on the web to control the displacement of the fluid in said one direction, thereby interfering with or interrupting movement of said rotary members and causing said sealing elements to separate.