US2338032A - Means for supporting collapsible tubes - Google Patents

Description

D86. 28, 1943 J F E I 2,338,032

MEANS FOR SUPPORTING COLLAPSIBLE TUBES Filed Jan 21, 1942 INVENTOR, JOHN H. FR/DEN ATTORNE;

Patented Dec. 28, 1943 S FOR SUPPORTING CQLLAPSIBLE "TUBES John H. Fridn, Maplewood, N. .L, assignor to The.

Sun Tube Gorporation, Hillside, N. J., a corporation of New Jersey Application January '21, 1942, Serial No. 427,584

10 Claims.

This invention relates to attachments for use on the pins of a chain conveyor or the like for supporting soft-metal, collapsible tubes in transferring the same from one point to another. It relates also to an improved method of supporting thin-walled, soft-metal, collapsible tubes, particularly as they are subjected to drying temperatures.

In the production of collapsible tubes for the packaging of tooth pastes, shaving creams, and similar substances, as well as certain liquids, such as hair tonics, and certain solids, such as efferves'cent salts, it is customary to convey the tubes between various operations on elongated, slender pins extending "from a suitable support. The support may be simply a vertically disposed stand of a portable character or it may be of any other suitable form, such as an endless chain conveyor of the type disclosed in the Fridn Patent No. 2,164,768, granted July 4, 1939. The pins will ordinarily be about one-quarter inch in diameter and sufficiently long to carry tubes of the maximum length to be handled. Regardless of the diameters of the tubes, whether less than half an inch or more than an inch and a half, the same pins will be employed. This has been quite satisfactory in dealing with tubes or containers formed of tin, zinc or aluminum since these have been able to retain their shapes properly under the conditions encountered in their manufac ture. However, in dealing with tubes formed of softer metals, such as lead, lead-base alloys, or the like, it has been found that the tubes when suspended from horizontally extending pins of the character. mentioned have a tendency to sag and become egg-shaped or of catenary form in cross-section. This tendency is particularly pronounced when the tubes, while carried by the pins, are subjected to elevated temperatures, as in the course of drying an outer coating or printed design in an oven or dryer.

A primary object of the present invention has been to devise a method of supporting thinwalled, collapsible tubes formed of relatively soft metals so as to prevent distortion thereof asthey are conveyed through a dryer, and to accomplish this without adding excessive weight to the conveying means. I

Another important object of the invention has been to provide an attachment for pins of the character mentioned which will effectively p'revent the distortion of the thin-walled containers under the conditionsexplained.

A further object has been to provide an at: tachment of the ty e set some which as simple and inexpensive to manufacture and light in weight. Lightness is of extreme importance since a typical conveyor chain may have as many as 16,000 pins to which the attachment rnust be applied. If the means employed were of any considerable weight, the load placed upon the conveyor would render its operation prohibitive.

Still another object has been to provide an attachment which may be readily applied to and removed from the pins' of a conveyor so that the latter may be adapted with facility to handle tubes 'of'widely different diameters. It has been found that reasonable latitude is permissible in the diameter of the tubes carried by a particular attachment. Thus, no change in "the attachment is required in switching from tubes of one inch diameter to tubes of an inch and a quarter diameter. The slight distortion of the larger tubes which may take place is not seriously objectionable. However, for tubes of one and onehalf inch diameter an attachment of larger size proved attachment of the inventiom'and Fig. 2 is an enlarged detail View of several links of the conveyor chain, partly in elevation and partly in vertical section, as indicated by the line 2-2 in'Fig. 1, showing the improved attachment applied to the regular tube-supporting pins. I

As indicated in the foregoing, the invention may be employed in connectionwith a conveyor and dryer system of the type illustrated in the prior Frid'n Patent'No. 2,164,768. The conveyor chain of said system is adapted tobe shiftedcontinuousl'y through a definite cycle, the several successive portions being carried past a work station-and then into, through and out. of a drying chamber. At the work station collapsible tubes may be subjected to a coating or printing operationon a suitable'm'achine and then trans" ferred either by hand 'orautomatically to ,the pinsof the conveyor chain for transportation to and "through the drying chamberl 'Th'ehh'ain may be of any appropriate length and will ordinarily carry a large number, say between ten and twenty thousand, of the tube supporting pins.

Within the drying chamber the tubes are subjected to an elevated temperature so as to dry, as quickly as practicable, the coating or printed. matter applied to their surfaces. To effect a reasonably rapid drying action, and thus reduce the necessary length of the drying chamber, a temperature of about 220 F. should ordinarily be maintained. In dealing with substantially pure tin tubes, such as produced heretofore, it has been possible to operate the dryer at such a temperature, or even higher, since the tin tubes have been sufficiently stifi and rigid at such a temperature to retain their shape when supported by the pins of the conveyor. However, thin walled, collapsible tubes formed of softer or less rigid metals, or those affected more readily by heat, such, for example, as lead or certain lead base alloys of the type disclosed in the Derge application S. N. 386,463, filed on April 2, 1941, have been found to sag and assume a catenary, or egg-shaped, form in cross section, when suspended horizontally in the ordinary manner from the pins of a conveyor even though subjected only to temperatures of about 200 F. It is to overcome this dimculty that the present invention has been primarily devised.

Referring now to the drawing, a corner of a drying chamber has been indicated conventionally at If] in Fig. 1. Through tlns chamber a conveyor chain II is adapted to be moved, preferably continuously. It may be arranged in a series of loops in said chamber, in the manner disclosed in said prior Friden patent. In its travel through the chamber the conveyor is passed around a series of sprockets iii, only one of which is conventionally shown in Fig. l and any number of which may be driven as disclosed in said prior patent. At every second pivotal connection between the successive links of the conveyor chain an elongated pin 53 is provided. These pins, as indicated, may be about inch in diameter and '7 or 8 inches long. In dealing with pure tin tubes or others of equal or greater stiffness at elevated temperatures, as previously indicated, the tubes may simply be applied to the pins and freely hung therefrom. However, in dealing with tubes formed of metals which are less rigid at elevated temperatures, it has been found necessary to provide supporting surfaces more nearly conforming with the inner surfaces of the tubes in order to prevent substantial distortion of the walls of the tubes. If the enlarged supporting surface were provided by simply increasing the diameter of the pins it, the weight of these pins would become excessive. It would be difficult, if possible at all, to make the chains strong enough to support the load of such pins and the power required to advance the chain continuously would be relatively great.

In accordance with the present invention the tube supporting surface is provided by an extremely light-weight attachment it, two or more such attachments being preferably applied to each of the pins. Each of the attachments Hi, in the preferred construction, is formed largely of a cork body or filler it having a central passage 16 extending from end to end thereof. This passage is normally of smaller diameter than the pin I3 but due to the resilience and yieldability of the cork, the latter may be readily applied over the pin and held frictionally in place thereing on. If desired, the attachments for supporting the collapsible tubes may consist simply of the cylindrical cork members If. However, this is not entirely satisfactory due to the friction between the relatively rough surface of the cork and the inner surface of the tubes. This interferes with the rapid application and removal of the collapsible tubes in the course of the normal operation of the equipment. Moreover, the surfaces of the cork cylinders, and particularly the ends thereof, if left unprotected, would soon become damaged and thus interfere with their proper support of the collapsible tubes. To overcome these difficulties, an outer metallic shell has been provided around the main cork body. This shell is preferably formed by extrusion in substantially the same manner as a conventional collapsible tube. It may be formed of tin or any other extrudable metal or alloy of the character mentioned. A cylindrical body portion ll of the shell is adapted to tightly surround the cork body or filler and the outer or free end [8 of this cylindrical portion is curled inwardly over and against the end of the cork body. At its opposite end the shell is provided with a conical, inwardly tapered portion it? terminating in a short, cylindrical neck 2d. Neck 259 has a bore 2| therethrough of slightly greater diameter than the pin Conical portion it of the shell is preferably relatively thick and rigid so as to resist distortion or indentation without the support of a filler, and the neck or collar 20 is of the same, or even greater, thickness. However, the rain, cylindrical body portion ll of the shell may be quite thin, like the wall of a conventional collapsible tube, since it will be held against any substantial indentation and distortion by the cork filler.

In the formation of the shell of the attachment, it is simply necessary, after extrusion of the from a disc-like slug, to trim off the two ends by appropriate cutting operations. This will serve to trim the shell to the desired length and also provide the neck with the desired openfhe form of the shoulder it and neck 26 may, if desired, be modified. For example, these may present a substantially spherical configuration. The neck may, in that event, be eliminated altogether. Preferably, however, the form and construction is such that the forward end or nose of the attachment is relatively rigid or stiff and also such as to facilitate the application of a collapsible tube to the pin carrying the attachment and its removal therefrom. The operator, in quickly applying tubes to the pins of the moving chain, will have the inner, open ends of the tubes conveniently guided by the inclined or curved shoulder i9 up to and over the main body portion. i? of the shell.

The outer diameter of the cylindrical portion ll of the cell or the attachment is preferably nearly the same as the inside diameter of the collapsible tube. If a reasonably close fit is provided, substantially all distortion of the col- F lapsible tube is prevented. On the other hand,

the fit should be sufiiciently loose to enable the containers to be applied and removed with facility. The clearance should be sufficient, furthermore, to permit the relatively free passage of air between the tube and the attachment so as to avoid the creation of pressure or a vacuum in the application and removal of the tube. This, however, may be achieved in other ways, as by the provision of appropriate passages through the pin H! or through the attachment. As Dreviously indicated, the diameter of the tube may exceed that of the attachment by as much as /4 of an inch, or even slightly more, since the distortion of the tube will not be objectionably great under these conditions. Thus, it is possible, without changing the attachments I4, to use the same conveyor for tubes varying as much as about A; of an inch in diameter. When tubes of greater variation than this are to be applied to the conveyor chains, the attachments M should preferably be replaced by a new set of larger or smaller attachments more closely approximating the diameter of the tubes to be dealt with. This substitution of one set of attachments for another may be readily accomplished inview of the simple frictional connection of the attachments with the supporting pins.

As indicated, the main body or filler I 5 is preferably formed of cork, due to the admirable properties of this material, but other filler substances may be employed. Important considerations in the selection of the main body or filler are that it shall be of relatively light weight and shall be capable of withstanding the elevated temperature and drying action of the dryer. It should also have a certain amount of resilience and compressibility to enable it to be frictionally held by the pins. Cork substitutes having these properties may be employed.

While an illustrative form of the invention has been described in considerable detail, and certain variations have been suggested, it will be understood that other modifications may be made without departing from the general principles and scope of the invention.

What I claim is:

1. A conveyor for collapsible tubes which comprises a conveyor chain, a plurality of pins of relatively small diameter projecting therefrom, and means detachably mounted on each of said pins for increasing the diameter of a portion thereof to a dimension approaching the internal diameter of said collapsible tubes, said means being formed largely of light-weight material and being provided with a smooth peripheral surface having a section of gradually reduced cross section facing toward its outer end.

2. A conveyor for collapsible tubes which comprises a conveyor chain, a pin of relatively small diameter projecting therefrom, and means detachably mounted on said pin for increasing the diameter of a portion thereof to a dimension approaching the internal diameter of said collapsible tubes, said means being formed largely of cork and having a smooth, thin-metal outer shell.

3. A conveyor for collapsible tubes which comprises a conveyor chain, pins of relatively small diameter projecting therefrom, and means mounted on said pin for increasing the diameter of a portion thereof to a dimension approaching the internal diameter of said collapsible tubes, each of said means comprising a thin metallic shell and a lightweight filler substantially filling said shell and adapted to surround one of said pins and frictionally grip the same.

4. An attachment for the pins of a conveyor for collapsible tubes which comprises a thin metal shell, and a lightweight filler in said shell having a passage therethrough adapted to receive said pin and frictionally grip the same.

5. An attachment for the pins of a conveyor for collapsible tubes which comprises a thin metal shell, and a lightweight filler in said shell having a passage therethrough adapted to receive said pin and frictionally grip the same, said shell having a nose of gradually reduced cross section toward its outer end adapted to facilitate the application of a collapsible tube thereto.

6. An attachment for a conveyor pin for collapsible tubes which comprises a thin-metal shell, and a lightweight compressible filler in said shell having a passage therethrough of smaller diameter than said pin adapted to receive said pin and frictionally grip the same.

'7. An attachment for the pins of a conveyor for collapsible tubes which comprises a thinmetal shell having a cylindrical body portion and a pointed nose portion, and a lightweight, compressible filler in said body portion, said filler and nose having alined passages therethrough adapted to receive said pin.

8. An attachment for the pins of a conveyor for collapsible tubes which comprises a thinmetal shell having a cylindrical body portion and a pointed nose portion, and a lightweight, compressible filler in said body portion, said filler and nose having alined passages therethrough adapted to receive said pin, the free end of said body portion being curled inwardly over the end of said filler.

9. An attachment for the pins of a conveyor for collapsible tubes which comprises a thinmetal, shell having a cylindrical body portion and a pointed nose portion, and a cork filler in said body portion, said filler having a passage therethrough adapted to receive said pin for frictional connection of said attachment and pm.

10. An attachment for the pins of a conveyor for collapsible tubes which comprises an extruded, thin-metal shell having a cylindrical body portion, an inwardly directed shoulder and a neck adapted to surround one of said pins, and a lightweight, compressible filler in said body portion, said filler having a passage therethrough adapted to snugly receive said pin.

JOHN H. FRIDEN.

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