US2380054A - Means for welding - Google Patents

Description

A. J. LAUTMANN July 10, 1945.

MEANS FOR WELDING 3 Sheets-Sheet 1 Filed. Aug. 2'7, 1943 HUT July 10, 1945.

A. J. LAUTMANN 2380,05 1

MEANS FOR WELDING Filed Aug. 27, 1945 I5 Sheets-Sheet 2 FH/Gif y 1945. A. J, LAUTMJANN ,5

MEANS FOR WELDING Filed Aug. 27, 1945 3 Sheets-Sheet 5 Jib rrz egg Patented July 10, 1945 MEANS ron WELDING Alfred J. Lautmann, Detroit, Mich, assignor to Iodent Chemical Company, Detroit, Mich., a

corporation of Michigan Application August 27, 1943, Serial No. 500,201

2 Claims.

This invention relates to the sealing of filled metallic collapsible tubes, such as are used for tooth paste, cosmetics, and like commodities.

It has, been the general practice after the filling of a collapsible tube is accomplished, which is done through the open bottom thereof, to flatten the tube so that its bottom wall portions are in juxtaposition with its free edges contiguous and then to fold these edges over upon themselves one or more times. The folded end then is secured by means of a clip of stiffer metal fastened thereto. This method of 0105 ing, which requires the addition of a clip, materially adds to the cost, and sometimes does not provide a good or hermetic seal for the tube bottom. The lack of a satisfactory seal frequently becomes objectionable in such instances for example, as during the handling, and particularly during shipping of collapsible tubes for sometimes the tubes are so jammed or deformed that the contents thereof may be forced outwardly through the folded bottom which -may stain or destroy the desired appearance and serviceability of the tube or package therefor to such an extent as to make it unmerchantable.

Various efforts have been made to seal the juxtaposed edges by interfusion but such known instances involve costly machines, impractical clamping devices, and ineflicient complicated sealing. devices requiring an excessive amount of electric current.

It is, therefore, an object of the present invention to provide a novel .machine which will close and hermetically seal a filled collapsible tube or the like entirely automatically.

Another object is to provide novel means on an automatic closing and sealing machine to effect a liquid and gas-tight joint in the nature of a hermetic seal at the closed bottom of collapsible' tubes, which means is highly efficient in use and inexpensive to operate.

A further object, is to provide a novelly constructed automatically actuated electric welding or interfusion device operable to effect continuous uniform welding of the bottom edges of a collapsible tube or the like.

Yet another object is to provide a welding device for use in an automatic tube closing machine which, while being entirely self-contained, will be operable dependently with operating mechanisms of such, machine.

Another object is to provide. a novel method of operation to hermetically seal the closed bottom of a collapsible tube or the like so as to eifect a liquid and gas-tight joint.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments and the principle thereof and which I now consider to the best mode in which I have contemplated applying that principle. Other embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired by those skilled in the art without. departing from the present invention and the purview of the appended claims.

In the drawings,

Fig. 1 is a side elevational view of a known form or a closing and sealing machine embodying the features of the invention;

Fig. 2 is a plan view of the machine;

Fig. 3 is an end elevational view of the machine showing the timing gear mechanism housing removed;

Fig. 4 is an enlarged detail view in. plan of the tube closing mechanism;

Fig. 5 is a side elevational view of the mechanism, shown in Fig. 4, taken substantially along line 5- 5 of Fig. 2;

Fig. 6 is an enlarged. front elevational view of an embodiment of the tube'welding device;

Fig. 7 is an elevational view taken in a plane at right angles to the Fig. 6 disclosure, showing the tube conveyor chain and a part of the machine frame in section;

Fig. 8 is a sectional view taken substantially on line 8-8 of Fig. 6;

Fig, 9 is a sectional view showing the folding mechanism, taken substantially along line 9-9 of Fig. 2;

Fig. 10 is a view showing. a fragment of a collapsible tube after its end has been hermetically sealed by welding;

Fig. 11 is another fragmentary view of the colliapsible tube, showing its sealed end folded; an

Fig. 12 is a view similar to Fig. 6, showing a modified form of welding device.

The collapsible tubes H) to be closed, sealed and folded, are filled through their open. bottom, bottom side up, in a suitable machine wherein they are automatically conveyed ina step-by-step movement into successive stations of rest for the various operations required to effect the desired operations. A typical machine of this character is generally illustrated in Figs. 1, 2 and 3, inclusive. This machine in cludes a supporting frame II embodying legs I2 and a bed plate or top I3 upon which the various devices for operating on the tubes are mounted. The tubes Il! may be carried into these various devices or stations by any suitable mechanism such as an endless conveyor I4 consisting of interconnected links, each carrying a holder or cup I5 for supporting the tubes. The conveyor I4 travels longitudinally of the machine along suitable supporting guides I6 and I1 and is supported at its ends by sprocket wheels I8 and IS. The sprocket wheel I9 is driven to thereby drive the chain I4. As shown, the wheel I9 receives its driving force through a gear 2| mounted upon its shaft 22 and operatively associated in a manner to be described hereinafter with a suitable source of operating power.

The tube supporting cups I5 preferably are metallic or otherwise electrically conductive and they are spaced uniformly along the conveyor I4, at such distances apart as to properly position the tubes so that work may be performed on them simultaneously at each of the various operating stations. Certain of these operations require that the movement of the cups be momentarily retarded, consequently, means is provided to give the conveyor an intermittent movement, each movement being equal to the spacing.

To obtain the required intermittent movement of the conveyor, suitable drive mechanism is provided, which may be a conventional Geneva movement. As best illustrated in Figs. 1 and 3, this drive mechanism includes the gear 2| which meshes with a pinion 23 carried on one end of a stud shaft 24, the other end of which carries a slotted plate 25 constituting one element of the Geneva movement mechanism. A driving element 26 carried on a second stud shaft 21 in cludes a face plate 28 recessed as at 29 at one side of a roller 3| carried thereon. Upon rotation of the driving element 25, the roller 3I engages in one of the slots 32 of the plate 25 to rotate said plate a distance equal to the spaning between adjacent slots. During the interval of rest, movement of the conveyor and its drive mechanism is prevented in the well known manner by engagement of plate 28 with a recessed edge of the slotted plate 25.

The stud shaft 21 carrying the driving element 26 also carries a gear 33 movable with said element. This gear meshes with a gear 34 carried on a main shaft 35 extending longitudinally of the machine above the top plate I3 and jour-- nalled at and intermediate its ends in bearings 36. The longitudinal shaft 35 is driven by a spiral gear 36 (Fig. 9) meshing with a gear 31 securely mounted on a transverse shaft 38. The shaft 38 is driven through a clutch 39 having driving connection by a belt M with a pinion 42 carried on a shaft 43 mounted below the top plate I3. The shaft 43 also carries a sprocket 44 which is operatively connected by a silent chain 45 with an electric motor 45, the operation of which may be controlled by a switch 41. Operation of the entire mechanism is controlled through the clutch 39 by a lever 48 extending be neath the top plate I3 and operable through a vertical shaft 49 to move an operating fork 5!.

In use of the machine, the filled collapsible tubes I 0 in the cups I5 are moved or carried over the length of the machine in a step-by-step movement during which movement they are successively positioned beneath various units which first collapse or fish-tail the open upper end of the tube to dispose its walls at the end portion in juxtaposition and then weld or otherwise inter fuse the juxtaposition edges of the tube. The tube end thus sealed may then be folded over in one or more folds to reinforce the tube bottom and protect the welded edge so as to prevent ultimate leakage resulting from the application of internal pressure.

The first step of closing the tube ends may be accomplished by any suitable mechanism. One form of mechanism for this purpose, best disclosed in Figs. 4 and 5, consists preferably of a pair of opposed reciprocable jaws 52 operatively connected for movement in unison to engage and squeeze the open end portion of the tube together tightly. Operation of the jaws may be effected through reciprocable movement of a slide 53 guided in a bearing block 54 carried on the top plate t3. The slide has a roller 55 at its rearmost end operatively engaged in an eccentric groove 56 in one face of a cam member 57 fixedly secured on the longitudinal main shaft 35. This mechanism is such that one complete rotation of the cam 51 in timed relation to the stop action of the conveyor I4 will move the jaws 52 through one cycle, that is, move them into their closed position and then their normal open position while the conveyor is at rest.

Obviously, some of the contents of the tube may be forced out of the collapsed end during the pressing operation, which excess material cakes upon the jaws and may hinder further operation. To remove this excess material, a suitable suction cup 58 may be mounted for vertical reciprocation above the clamp jaws 52 in a bracket 53. The cup is connected through a pipe 53 with a suitable source of negative pressure and is adapted to be moved downwardly immediately after the clamp jaws 52 have clamped the end of the tube so as to completely enclose the upper end of said clamped tube and effectively draw off any surplus material. Vertical reciprocation of the suction cup may best be obtained by providing a rack GI on one side thereof which meshes with a pinion 52 operable through a rack 63 formed on the end of a spring controlled cam actuated-reciprocable plunger 64. A roller 55 carried on the rear end of the plunger 64 rides upon the circumferential face of the cam member 51 in which a recess 66 is provided. It should be obvious that during one complete revolution of the cam member 51, the roller I35 drops into the recess 66, thus rotating the pinion B2 to momentarily lower the suction cup 58.

It should be understood that the mechanism above described does not constitute novelty of the present invention and has been described only to the extent required to illustrate the operation of the present invention.

After the upper tube end has been flattened, the tube is carried, through further movement of the conveyor into the next stop station where further operations, later described, are effected. However, during movement of the collapsible tube between these two stations, the collapsed or fiattened end is welded or otherwise interfused to provide a liquid and gas-tight joint at its edges in the nature of an hermetic seal. To this end, a novel welding or interfusion device; best shown in Figs. 6, 7 and 8 is provided on the machine. As shown, the top plate I 3 of the machine carries an upwardly extending bracket 6'! having a block 68 of suitable ir'i'si'ilation material extending forwardly' from its. upper and provided on its forward end with a metallic plate-69. The: plate 69 is suitably bifurcated or otherwise formed at one end to receive the upper end of: a cylindrical holder H pivotally secured thereto'bya pin 12. The l'i'older Tl provides a mountingfor an electrode preferably in the form of a carbon stick 13 which may readily be adjusted in length upon manipulation of set screws 14 so as to dispose its free pointed end substantially in the'path of but below the top' plan of the upper juxtaposed edges of the closed tube I so as to be engaged thereby when said tube moves therebeneath. :A spring 15 is provided to create a firm yieldable contact between the electrod 13 and the upper end edges of the tube for a purpose to be more fully understood as the description of the welding operation proceeds.

The base of the bracket 81 includes a block 16 of suitable insulation material to" provide a support for one end of ahorizontally disposed conductor shoe H, the other endof which is supported ina similar insulation block 16 supported in a bracket 18. Asbest shown in Fig. 8, the shoe H has rearwardly extending pins I9- extending through the. respective installed supports and each pin is surrounded by a tension spring 8! so'that' the shoe normally is urged forwardly away.

from its supports whereby it is disposed in the path of the cup l= carried by the. conveyor 14.

Consequently, as a. cup advances to carry the tube therein into contact with the electrode 13, it initially contacts the shoe and tensions the springs 8| whereby a firm sliding contact is maintained between the shoe and cup. Both the shoe Ti and the electrode H are suitably connected, as shown diagrammatically in Fig. 6, with any available source of electric current, such as for. example, the storage battery 82. It should be evident at this time that when the metallic cup l5 makes contact with the sho IT, during its movement along the machine, the electric current enters said cup and passes into the metallic collapsible tube Ill; As soon as the juxtaposed edges of the flattened tube end contact the end of the carbon electrode 13, the circuit is complete and because of the high resistance of the carbon electrode 13, the material of the tube is melted so as to cause interfusion of the juxtaposed edges as the tube moves past the electrode.

It is important that a uniform interfusion or welding be efiected and to this end it is essential that movement of the conveyor and pressure of the electrode on the work during the welding operation be constant and that the flow of cur-- rent be uniform. To be otherwise may result in a weak spot in the welding because insufficient heat or excessive heat applied at any one point will result in non-uniform melting. For example, should an excessive amount of current momentarily be applied, there will be an excessive melting of the tube walls and as a result a weak spot will develop. Similarly, should less than the required current be applied, the fusion may be incomplete thu leaving a weak and perhaps a broken spot. Likewise, should movement of the conveyor or pressure of the electrode be irregular, too much or too little heat will be applied at certain points along the welded seam. The result is the same, an imperfect joint. It is, therefore, desirable but by no means essential that a storage battery be utilized as the source of supply because of the even flow of current obtained. The Welding device herein disclosed is particularor stationwh-ich inthe instant disclosure, con-- sists of suitable automatically operable conventional mechanism for foldin the flattened andwelded' end portion of the tube over upon itself either one or two times to protect the welded edge and further reinforce the tube end. As best illustratedin- Fig, 9-, the folding mechanism is actuated by two cams 8'3 and 84' fixedly secured upon the transverse: shaft 33; The cam elements 83 and 84 are each provided with circumferential grooves 85' and 86' respectively, each of which coa'cts with pins 87 and 88 respectively, on slidable bearing blocks 89 and BI respectively, carried in a bracket 92 mounted on the top face of the plate l3. The cams 8-3- and 84 are arranged so that upon being rotated in unison, they move the blocks 89- and 9! towards each other in timed relation to the stop period of the tube conveyor [4. When the blocks move inwardly towards each other, an anvil 93 mounted on one block is carried into contact with one side of the flattened tube end which is backed up by one arm of a bell crank 94 carriedv on the other block. This contact of the anvil- 93. with the. flat tube end limitsforward movement of said anvil. The anvil is, however, yieldably mounted in the block 9|, consequently, said block continues forwardly independently of the anvil 93 to carry a roller 95 mounted on the downwardly turned end of an associated arm 96 against the upwardly extending end portion of the flattened tube end, folding said end portion downwardly against the top of the bell crank 94 as illustrated.

The parts are then momentarily withdrawn into their initial apart position by the cams. Continued rotation of the cams again moves the blocks 89 and 9| with their complemental parts inwardly towards each other, whereupon the free end of the ball crank arm 94 engages the initially bent-over portion of the collapsible tube to press it down firmly into tight engagement with the flattened tube end. During this final folding operation, the flattened end of the tube is backed up by the plunger 93. If a double fold of the kind illustrated in Fig. 11 is desired, the folding mechanism described and illustrated in Fig. 9, may be duplicated by providing such mechanism on each side of the transverse shaft 38, as generally illustrated in Fig. 2, the spacing between said folding devices being equal to the spacing between the holders carrying the collapsibl tubes.

It will b observed that the welded edge of the folded tube is adequately protected and reinforced against inadvertent breakage and subsequent leakage. It should be understood, however, that the welding operation, when properly accomplished in the manner described herein, will result in a, seam that will resist all normal pressures or forces tending to rupture the collapsible tube inasmuch as th welded seam will be as strong as and perhaps stronger than the material forming the tube.

Although a preferred embodiment of the welding device has been described hereinafter, it

should be understood that other types of devices, which will serve with equal satisfaction to provide a liquid and gas-tight hermetic seal at the tube end, may b employed. Such a modification is illustrated in Fig. 12 wherein the electrode holder 1Ia has mounted thereon, but insulated therefrom, two wipers 91 and 91a. having a common connection with one terminal of the electric circuit. The other terminal of the electric circuit is connected to the holder Ha as before. In operation the collapsible tube I0 is carried forward by the conveyor M so that its flattened end edges initially contact the wiper 91a. Continued movement carries the edges into contact with the spring pressed electrode 13 whereupon the circuit is completed through wiper 91a, the tube 10 and the electrode 13 so as to heat the electrode and melt and interfuse the juxtaposed tube edges in contact therewith. As the tube continues its movement relative to the electrode 13, the wiper 81a finally moves off of the edge of the tube. The circuit is not broken by this disconnection because the other wiper 97 is now contacting the tube edges. Accordingly, the circuit is closed and the electrode 13 becomes et'- 1 fective to weld the tube ends immediately upon contact being made between the electrode and the tube edges, which contact is maintained until the electrode passes off of the opposite end of said edge. In other respects the welding device described is like that previously described and shown in Fig. 2 and like numbers identify corresponding parts. It should be obvious, however, that this form of construction may be simpler and less expensive in that a separate yieldably mounted shoe is not required and that the cups or holders 15 supporting the tubes need not be of metal or of any other conductive material.

What I desired to claim as new and secure by Letters Patents is:

1. In a machine for sealing the collapsed end of a filled metallic tube having a metallic carrier for said tubes, a bracket on said machine, a shoe mounted on and insulated from said bracket connected to one terminal of an electric circuit, an electrode mounted on and insulated from said bracket and connected to the other termi-- nal of said circuit, means to move said carrier into contact with said shoe and carry the collapsed end of the tube into contact with the electrode to close the circuit so as to heat the electrod and melt and interfuse said end along the line of contact with said electrode.

2. In a machine for sealing the collapsed end of a filled metallic tube having a metallic carrier for said tubes, a bracket on said machine, a shoe yieldably mounted on and insulated from said bracket connected to one terminal of an electric circuit, a carbon electrode yieldably mounted on and insulated from said bracket and connected to the other terminal of said circuit, means to move said carrier into firm contact with said shoe and carry the collapsed end of the tube into firm contact with the electrode to close the circuit so as to heat the electrode and melt and inter- Iuse said end along the line of contact with said electrode.

ALFRED J. LAU'I'MANN.

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