US2276332A - Method of and apparatus for attaching end members to container bodies - Google Patents

Description

March 17, 1942. R NQRDQUIST 2,276,332

METHOD OF AND APPARATUS FOR ATTACHING END MEMBERS TO CONTAINER BODIES Filed Nov. 7, 1940 ATTORNEYS Patented Mar. 17, 1942 TNT FFIQE METHOD OF AND APPARATUS FOR ATTACH- ING END MEERS TO CONTAINER BODIES Application November 7, 1940, Serial No. 364,732

8 Claims.

The present invention relates to a method of and apparatus for attaching fibre end members to fibre container bodies and has particular reference to temporarily reforming an end member while it is in place in a container body and securing the reformed end member to the body in such a manner that after being secured it will spring back into a predetermined condition to form a permanent wall of the container thus produced. In some respects the apparatus of the instant invention is an improvement on the Can end assembling machine disclosed in United States Patent 2,200,276, issued May 14, 1940, to John M. I-Iothersall, et al.

In the manufacture of fibre containers having separately applied end members permanently secured to the container body it is often desired that the end or ends of the finished container have a difierent shape than that of the original shape of the end member. This usually necessitates a separate pre-forming operation to prepare the end member for use.

As a specific example, in the manufacture of rectangular fibre containers having fiat fibre end members it has been found that when the end members are out from material that has been rolled up on a reel for a long time they retain the curvature of the roll instead of being flat. When such end members are secured to their container bodies it has been found that this curvature still remains in them and results in the container having other than a fiat end.

If the original curvature of the end member extends inwardly in relation to the container body the end corners of the finished container will be high and conversely if the end member bows outwardly the corners will be low. In the latter case, when such an end member serves as the bottom of the container the latter will not stand up properly.

In order to overcome this difiiculty, pre-forming of the end member or bending it in the reverse direction has often been resorted to but this requires another operation in the manufacture of the container. Often the set in the material is of a permanent nature and requires elaborate steaming or heating operations to eliminate it. This increases the cost of the container so that it is sometimes prohibitive.

The instant invention contemplates overcoming these difiiculties by subjecting the original end member to a strain while it is in place in its container body to temporarily spring it out of its original condition, then securingit to the body and then releasing the strain so that the secured end member will spring back into a desired permanent condition. I In the case of end members which are distorted by having an original curved set or bowed condition, the inventioncontemplates springing the end member a predetermined amount in a direction opposite to that of its curvature whileit is in the container body and securing it to the body while in this condition so that after it is secured it will spring back a sufiicient amount to result in a permanent flat or straight condition thus providing a fiat end for the container.

In some cases it may be desired to have the ends of the container bowed inwardly or outwardly a predetermined amount instead of being fiat and to such cases the instant invention is equally well adapted even though the end members as originally received may be in a perfectly flat or in a curved or bowed condition.

An object therefore of the invention is the provision of a method of and apparatus for attaching end members to container bodies wherein an end member is subjected to a predetermined strain while in place in a container body to temporarily spring it out of its original condition and is secured to the container body while in this strained condition so that after it is secured it will spring back into another desired condition which is permanent and which is different from its original condition.

Another object is the provision of such a method of and apparatus for attaching end members to container bodies whereinan originally distorted end member received in place within a container body is partially reformed into another shape while in the body and secured to the body while so reformed so that it will return to a desired shape after the securing operation.

Another object is the provision of a method and apparatus of the described character wherein curved end members loosely disposed in container bodies are flexed within their elastic limit and in a direction opposite to their original line of curvature while in place within the bodies and secured to the bodies while so flexed so that after the securing operation the flexed end members will spring back into a flat condition to produce a desired flat end wall for the container.

Another object is the provision of such a method of and apparatus for attaching end members to container bodies wherein the changing of the shape of the end members is effected while they are disposed in their container bodies so that a pro-forming operation on them, may be eliminated, and is effected from the outside so that end members may be applied to the open ends of container bodies which have their opposite ends already closed and in which access to the interior of the container is thereby prevented.

I Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

Referring to the drawing:

Figure 1 is a vertical sectional view of certain of the principal parts of a fibre can body and end sealing apparatus embodying the instant invention such apparatus being suitable for carrying out the steps of the present method, the view showing a can body in place in the apparatus;

Fig. 2 is an end elevation of the mechanism as it would appear when viewed along the line 22 in Fig. 1;

Fig. 3 is a sectional view taken substantially along the section line 33 in Fig. 2 with parts removed;

Fig. 4 is an enlarged fragmentary vertical sectional view taken substantially along the line 44 in Fig. 2, and showing essential curved flange engaging surfaces of squeezing jaws and sealing head for imparting the desired flexure or curvature to the end during sealing;

Fig. 5 is a cross sectional detail of one end of a fibre container body with a distorted or curved end member loosely inserted;

Fig. 6 is a view similar to Fig. 5 and showing the end member sprung out of its original condition prior to securing to the body; and

Fig. 7 is a view similar to Figs. 5 and 6 but showing the finally sealed end member after it has assumed its flat sealed condition.

As a preferred embodiment of the instant invention the cans to be operated upon are preferably of square cross section and are made of fibre material. Such cans include a tubular body A (Fig. 5) having an inwardly extending shoulder bead B which sets off a flange C which surrounds the body. A fibre end member D is loosely in place within the body and is in engagement with the shoulder bead B.

As one example, the end member D may be of distorted, curved character, having been cut from a web of fibre material which has been rolled up for some time as hereinbefore explained, such an end member being used in its original curved condition to save time and expense involved in a separate straightening operation.

The end member D is temporarily held in place within the can body by the flange C which is partially folded over in overlapping relation to the outside of the end member, the flange along each side of the body being disposed at an angle to the end member. The flange, the end member and the shoulder bead B further carry a marginal band of thermoplastic adhesive which is heated to a tacky condition prior to the sealing operation. It is in this condition that the cans to be sealed are received.

As a step of the instant method invention the distorted or curved end member is first subjected to a strain or outside pressure to temporarily spring it, within its elastic limits, out of its original condition or shape while it is in place in the can body. curved end member is flexed in a direction oppo- In the example given, the.

site to that of its original curvature so that it extends outwardly as shown in Fig. 6.

While the end member D is in this flexed condition, the partially folded flange C of the can body A is completely folded over and pressed tightly against the tacky marginal edges of the end member to force the latter into close engagement with the shoulder bead B. This unites the flange, the end member, and the shoulder bead to produce a strong hermetic seam or joint the parts of which are bonded together by the thermoplastic adhesive. This joint secures the end member to the can body.

After sealing of the flexed end member D to the can body, the strain or pressure on the end member is released and this permits it to spring back toward its original shape. However, by controlling the pressure applied to the end member it may be flexed any predetermined amount so that it will spring back into a desired position to produce a permanent end wall for the can.

In the example now being considered, the ultimate desire is to produce a flat'bottom for the can, as shown in Fig. '7. Hence when the inherent springy nature of the material of which the end member is made and the bonding properties of the sealed joint are taken into consideration, the exact pressure may be applied to the original distorted end member so that it will be flexed the proper amount to return or spring back to the desired permanent condition. By utilizing these principles any originally distorted end member or any perfectly flat end member may be sprung while in place in the can both to obtain a desired permanent position of the end member after it is sealed in place and thereby eliminate a costly pre-forming operation on the end member.

One form of apparatus for carrying out the above method steps of the invention is illustrated in the drawing which shows the principal parts of the can sealing station of the can end assembling machine disclosed in the above mentioned Hothersall Patent 2,200,276.

The cans A to be sealed are preferably advanced through the machine in a step-by-step or intermittent motion and in a horizontal position by a conveyor II. This conveyor is intermittently actuated in any suitable manner in time with the other moving parts of the machine and preferably in the manner disclosed in the Hothersall Patent 2,200,276.

During its travel through the machine a can is brought to rest at the sealing station where the end to be sealed is adjacent a sealing device, generally indicated by the numeral I2. The opposite end of the can is adjacent a pusher device IS.

The pusher device l3 includes a slide I5 which is carried in a bracket l6 secured to the top of a frame I! which constitutes the main frame of the machine. The slide may be reciprocated in any suitable manner in time with the other moving parts of the machine to shift the can transversely of the conveyor H and to push the end of the can to be sealed into the sealing device [2.

The sealing device I 2 includesa horizontally movable sealing head or punch 25 (Figs. 1, 2, 3, 4) which slides in a bearing 26 formed in a bracket 21 bolted to the main frame ll. This punch is moved toward and away from the end of the can to be sealed, the punch being actuated in any suitable mannerrin time with the other moving parts of the machine. For this purpose the outer end of the punch is formed with a stem 3|. whichis carried in a bearing 32 inthe bracket 21.

The punch is square in cross section when the can being operated on is square and its inner end is hollow. This hollow end terminates in a sealing face Two opposite and parallel sealing surfaces of the punch are fiat as indicated .by the numeral '52 while the other two sealing surfaces are curved inwardly and are marked with the numeral 53.

While the sealing head 25'moves toward the end of the can to be sealed, a plurality of can holdingv elements are moved into position against the canto prevent its displacement and to flex the end member D as hereinbefore mentioned. These holder elements include a plurality of levers 55 (Figs. 1 and 3), preferably four in number and these levers are located one adjacent eachcorner of the can. These levers are mounted on pivot pins 55 carried in housing blocks 5'! formed as a part of the bracket 21.

The inner ends of the levers are formed with right angle jaws 6| having oppositely disposed and parallel holding and flexing faces 62. Two of these surfaces are flat as indicated by the numeral 63 and two are inwardly curved or bowed and marked with the numeral 64 and these surfaces correspond to and cooperate with the surfaces 52, 53 of the sealing head 25. The jaws are shaped to fit around the corners of the can and to extend into and support the shoulder bead B. In their normal positions, the jaws are spread apart and are spaced from the can.

The outer ends of the levers 55 carry cam rollers 65 which engage against inclined cam surfaces 65 of block cams 61 secured on the stem 3! of the punch 25. Compression springs 68 interposed between the levers 55 and cover plates 65 on the housing blocks 5'! keep the cam rollers in engagement with the cam blocks.

Hence as the sealing head 25 moves toward the can the block cams 61 force the outer ends .of the levers 55 outwardly and rock the levers so that the jaws 6| move in around the can and engage against its shoulder bead B in opposition to the tension of springs 68. The sealing surfaces 52, 53 of the moving sealing head come into contact with the can flange C and immediately thereafter force the flange home against the can end member. The can end member is also moved against the shoulder bead B which is backed up by the curved and flat surfaces of the holding jaws 6|.

It is the cooperation of the curved and flat surfaces 52, 53 and 63, 64 of the respective sealing head 25 and jaws 6| that subject the end member D to a strain and thereby flex it the desired amount. It is also this cooperation of these surfaces that results in a squeezing action that produces the bonded joint or seam hereinbefore explained. The tacky adhesive provides the bond which permanently secures the flexed end member to the can body. This completes the sealing of the can.

After such a sealing operation the sealing head 25 moves away from the can and the block cams 6'! move with it to release the can supporting and flexing jaws 6! by reason of pressure exerted by springs 68. This relieves the flexing strain on the flexed end member and hence it springs back into the desired straight and flat position for the described character of can. The released and sealed can is thereupon withdrawn from the sealing head and returned to its original position in the conveyor so that it may be further advanced and finally discharged from the machine.

In order to prevent the tacky adhesive from collecting on the sealing head parts and toquicken the setting and hardening of the adhesive on the sealed can, the holding jaws 6| are maintained in a cooled condition. This cooling is preferably effected by circulating a cooling medium such as cold water, brine or the like through the parts to be cooled.

Circulation of the cooling medium is elTective through the passageways 8| (Fig. 3) which are formed in the jaws and. which are in communication with an inlet pipe 82, an outlet pipe 83, and connecting pipes 84 which connect individual passageways of the different jaws. The cooling medium thus enters one jaw, circulates through it and through all the other jaws, and then leaves by way of the outlet pipe 83. The inlet pipe 82 may lead from any suitable source of cooling medium and the outlet pipe 83 may return to this source or may lead to any suitable place of deposit for the cooling medium.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts and that changes may be mad in the steps of the process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim: I

l. A method ofattaching end members to container bodies, which comprises engaging a body having a curved end member loosely inserted therein with a rigid medium of different/curvature and clamping the body and end thereagainst to change the curvature of said end member and temporarily spring the same from its original condition, permanently securing the sprung end member to the container body, and releasing the clamped pressure on the secured end member so that it will spring back into an intermediate desired predetermined condition.

2. A method of attaching end members to container bodies, which comprises engaging a body having a curved end member loosely inserted therein with a rigid medium of opposite curvature and clamping the body and end thereagainst to thereby reverse the curvature of said end member and temporarily spring the same from its original condition, simultaneously securing the end member to the container body, and thereafter releasing the clamped pressure on the secured end member and body to permit the end to spring back into an intermediate desired predetermined condition to provide a permanent wall of the container so produced.

3. A method of attaching end members to container bodies, which comprises clamping a body having a curved end member loosely inserted therein against a rigid medium of opposite curvature to thereby oppositely flex said end member within its elastic limit while it is loosely retained in place on the container body to temporarily change its original shape, and as an incident to said clamping step permanently securing marginal portions only of the flexed end member to the container body so that after being secured in place and released from clamping pressure, said end member will return to an intermediate .predetermined configuration to provide a permanent wall for the container s'olproduced..

4. A method of attaching end members to container bodies, which comprises supporting a tubular container. body having a curved end member loosely assembled therewith, clamping said body and end against-a rigid medium of opposite curvature to reverse the curvature of said end member and temporarily spring the same out of its original condition, simultaneously folding an annular edge portion of the container body into overlapping relation against the marginal portion of said oppositely flexed end member and sealing the same in an hermetic end seam joint, and then releasing the clamped pressure on the secured sealed end member to permit the same to spring back into an intermediate position providing a permanent flat bottom for the container so produced.

5. In an apparatus for attaching end members to container bodies, the combination of complementary curved relatively movable means for clamping an oppositely curved end member therebetween to flex said end member into an oppositely curved configuration while it is loosely retained in a container body, said complementary movable means being further operative to secure the oppositely flexed end member to the container body, whereby after being secured said end member will spring back into an intermediate flat condition constituting a firm supporting wall for the container.

6. In an apparatus for attaching curved end members to container bodies, the combination of pivotally movable support instrumentalities for engaging the exterior of a body adjacent an end member loosely retained therein, said support instrumentalities having face portions curved in a direction opposite to the curvature of said end member, sealing means movable toward and relative to said support instrumentalities, said sealing means having a face portion curved to conform to the curvature of said support instrumentalit-ies, said instrumentalities and said sealing means cooperating to clamp therebetween the marginal portions of said assembled body and end members to flex and curve said end member from its original curved shape into oppositely curved configuration conforming to the curvature of said support instrumentalities and sealing means, said support instrumentalities and sealing means further cooperating to seal and secure the flexed end member to the body, whereby the secured end member will spring back into a flat configuration to provide a permanent supporting wall for the containers 7. In an apparatus for attaching curved distorted end members to container bodies, the combination of a plurality of movable jaws having curved faces for engaging a body on the outside thereof adjacent a curved end .member loosely retained therein, means for moving said jaws into engagement with said body adjacent marginal portions of said end, and a sealing head cooperating with and movable relative to said jaws and having a curved facewhich coincides with the curved faces on said jaws, the face curvature of said jaws and sealing head being in a direction opposite to the curvature of said container end member, said jaws and said sealing head cooperating in flexing the curved distorted end member a predetermined amount in a direction opposite to that of its original curvature while it is in the container body and also cooperating in sealing the flexed end member to the body, so that the end member will spring back into an intermediate flat straight wall after being so secured.

8. In an apparatus for attaching curved distorted end members to container bodies in which the end members are each disposed against a beaded shoulder of a said body and loosely retained in place by a partially folded over end flange on said body, the combination of a conveyor for moving a procession of the bodies along a predetermined path of travel past a sealing station, a pusher element disposed at the sealing station for shifting a body transversely of the conveyor in a direction axially of said body, a plurality of contractible jaws at said sealing station for surrounding an end of a shifted body to peripherally engage and support the beaded shoulder thereof, and a sealing head at said station movable into engagement with the supported end of said body, said jaws and said sealing head respectively having cooperating complementary curved and straight faces for clamping the engaged marginal portions of the container body and end member therebetween to flex said end member a predetermined amount in a direction opposite to that of its original curvature, said jaws and sealing head being further operative to simultaneously seal the partially folded flange of the body against the flexed end member while it is backed up by said jaws, to permanently secure said end to the body, whereby the end member will spring back into a flat, straight wall when the sealing head moves away from the body.

RONALD E. J. NORDQUIST.

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