US1877629A - Method for bending tubes of fiber and similar material - Google Patents

Description

Sept. 13, 1932. I REPLQGLE 1,877,629

METHOD FOR BENDING TUBES OF FIBER AND SIMILAR MATERIAL Filed Feb. 17, 1930 Patented Sept. 13, 1932 UNITED STATES PATENT. OFFI DANIEL BENSON REPLOGLE, OF BERKELEY, CALIFORNIA, ASSIGNOR TO THE COMMERCE GUARDIAN TRUST 80SAVINGS BANK, TOLEDQ'OHIO; TRUSTEE METHOD FOR BENDING TUBES F FIBER AND SIMILAR MATERIAL Application filed February 17, 1930. Serial No. 429,188.- 7

The invention relates to a .method for bending tubes constructed of'hygroscopic material such as vulcanized fiber, hard paper tubes, or tubes composed of other cellulose or fibrous material.

conveyed to the winding mandrel by anysuitable form of conveying means. As a. result of this operation, there is formed uponthe' mandrel a tube having awall which is substantially homogeneous. lVhen the windmg operation is completed, the tube itself is moist and it is then ordinarily subjected to a drying operation by which the moisture is removed.

The present invention relates to an improved method of bending such fibrous tubes after the forming mandrel has been removed. This may be accomplished before the wet pulp of which the tube is composed is permitted to dry, or if it is dried the tube may be moistened so as to condition it for'the bending operation, for it is a prerequisite that the tube shall be in a condition to bend, and in a moist condition they bend best. A moist paper or fibertube is easily collapsible since the walls thereof under these conditions possess little strength or resistance.

One of the problems which presents itself r in the bending of such tubes is to prevent the malformation of the tube and to maintain the circularity of the tube in cross section. I

have solved this problem by causing a yielding outward pressure to be exerted uniformly against the interior of a. moist tube during the bending operation, by means of gas pressure within the tube, and then removing the moisture from the tube while it is still subsure is preferably maintained within the'tube during and after the bending operation, and this is preferably accomplished by sealing thIsJ tube gas tight and applying heat to the tu e.'

According to the preferred embodiment of becomes moist and flexible. This flexibility i may of course be obtained. by employing a tube which has just been formed from the web or pulp and which has not been permitted to dry. .The essential feature,in any event, I

is to obtain the desired flexibility of the fibrous material of which the tube 'is. oom-' posed. Whenjthis flexibility has been obtained, the tube is inserteds-in a bending matrix and closed gas tightQ Heat is then applied to expand theii'airwithin the tube I and also to generate steam fromthe moisture contained within the tube walls. 'Suflicient heat is applied to produce a pressure which will prevent collapsing of the'walls of the tube .7 during the bending operation. Preferably the heat should beuniformly applied to the outside of thetube, both above and below, and in this manner substantially uniform temperatures inside and out of the tube are maintained. The preferable mode of supplying heat is by meansof gasburners which 7 may be very accurately regulated to produce the desired degree of pressure within the tube. V 1

} According to the preferred embodiment of the lnvention a number of tubes'may be bent at one time and in a single matrix, and in such case it is desirable that the gas burners be prof I vided with branches above and below the tubes, and corresponding in number with the number of tubes.v A single control device may be employed for regulating the supply of gas to all the branches.

1 When the gas pressure has' thusbeen obtained within the tube 'or'tubes, the bending forms or matrices and kept gas tight until the i hardening of thetubes is completed. This setting or hardening; operation is preferably.

accomplished by a continued supplyof heat,

' which performsthe dual operation of'drying the tubes and maintaining the internal gas dust and the like.

" ing bent;

pressure during such drying and heating operation.

The advantage of gas pressure for maintaining the circularity of the tubes over other means which have been employed for similar purposes is self-evident, namely the uniformity of pressure throughout the, tube, thus avoiding marring or ridging at any portion and providing a smooth interior or exterior surface. -Moreover, aperfect control of the pressure may be had where gas isused as the expanding medium by regulation of the heat supplied, the same heat serving both for drying and for maintaining pressure within the tu e.

While the gas pressure alone is sufiicient to perform the desired operation, nevertheless it is sometimes desirable to fill the tube with fine granular material such as moist sand, saw- It is notessential that the sand be moist, although this is preferable.

Such granular material assists in maintaining V thecircularity of the tube, particularly prior to the time that the gas pressure is sufficient to prevent collapsing. Where moist granular materlalis used, such moistureproduces steam on heating of the tube, which steam produces pressure to assist in maintalmng the circularity. If desired, where already fixed tubes are i to be bent, such fiber tubes may be first filled V with sand or granular material to insure the maintaining of circularity, and then while so filled may be soaked in water to obtain the de sired flexibility. Obviously when so filled there is no danger of the tubes collapsingbefore being placed in the bending matrices.

The bending opera-tion may be desirably performedin an apparatus set forth in the accompanyingidrawing, in which Figure 1 is a top plan view of the bending apparatus especially designed for bending gas filled tubes and for heating the gas during the bending and subsequent drying of the tubes. in order to maintain the proper degree of pressure within the tubes;

Figure 2 is a longitudinal sectional view of the apparatus, the section being taken through one of the tubes, certain parts being shown in elevation, this view showing the relation of parts when the tubes are in place withinthe forms, and just before the bending operation; 7 j o I Figure-3 is aview similar to Fig. 2 showing theparts of the device-when the tubes are be- Figure 4 is a detail vertical sectional view showing a means forheating the tubes, and

Fig. 5 is a detail of one of the extension plates attached to the lower forms.

As shown,'the bending device consists of bed member. 10, and anupper press member ll-pivotally connectedto the bed member by means of the hinge 12. The bed member carries the lower halves 18 of a plurality of- "tube forms, herein shown as three in number,

tubes are closed air tight by means of gaskets 16'which are held in place by caps 17, which in turn abut against projections 18 on the lower portion of the form. The caps 17 serve to protect the ends of the tube against injury or marring during the bending operation. To eachof the lower forms is pivoted an exprevent marring of the tube at that end of the tube form, as would obviously be the case if no such means were provided. In order to maintain each of the tubes gas tight, spring pressed closure members 20, of rubber or like material, are provided at the ends of the tubes opposite the gaskets 16. These closure mem bers are carried by threaded rods 21 extending through a bar 22, which is carried-by a lever 23 secured to one ofthe pivoted shields .19. Springs 24: react between the bar 22 an the closure -members 20. v In order to prevent collapsing-of the'moist tension shield 19, thepurpose of which is to fibertubes,heat is applied, which, expands the air withinthe closed tubes and generates steam from the moisture carried by the tubes.

To supply the necessary heat, gas burners25 and 26 above and below the tube formsare provided. Sufiicient pressure will be gener ated within the tubes by this heating operation to prevent collapsing-of the tubes as the upper form members are lowered to the position shown in Fig. 3, by means of an operating handle 27 or other operating means, and the form may be secured in this lowered position by means of a latch member 28, provided with a notch 29, which coacts with a pin 30 upon the operating handle 27. As the tubes are bent the extension shields 19 are rotated about their pivots 31' and prevent marring of the tubes at the ends of the lower tube forms 13. As the shields arerotated, the rod 23 carried by the central space, swings upwardly, carrying with it the bar 22 and the closure members 20, which swing in the same-arc as the tubes the bent form. The drying operation will be assisted by'the application of heat from the burners, 25 and 26. The gas pressure is maintained within the tubes until they have hardened sufficiently to prevent collapsing. It will be noted that accurate control of the temperature and pressure within the tubes may be had at. all times by regulating the themselves, and in this manner the gas tight flame from the gas burners, a valve 32 being provided for this pur ose. It is to be further noted that uniform eating at the top and bottom of the tubes is obtained by means of V the upper and lower series of burners 25 and V 26. Both upper and lower burners are branched and their number corresponds to the 7 number of the tubes to be bent, so that the te1nperatures and pressures will be equalized for all of the tubes undergoing the bending operation. The upper set of burners 26 is connected to the source of supply by flexible members 33, whereby the burners 26 are readily moved upwardly and downwardly with the upper hinged member 14 of the matrix. This arrangement is intimately connected with the improved process in that it permits heat to be applied to the top of the tube to supply the necessary pressure within the tube before the bending operation takes place, as clearly indicated in Fig. 2. hen theupper member 14 is lowered to the position shown in Fig. 3, the burner members 26 are likewise carried downwardly so as to remain in close proximity to the bent tube and maintain the desired gas pressure uniformly within the tubes durin the heating operation.

aving thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A method of forming a fixed bent fiber tube which comprises sufficiently moistening the tube to render it flexible, closing the tube gas tight, heating the closed tube sufficiently to generate gas pressure within the tube sulficientto maintain the circularity of the tube during bending, bending said tube while maintaining said gas pressure, and drying the gas tight closed bent tube to cause it to set by continued application of heat, thereby ing stress and simultaneously confining the outside of the tube to prevent radially outward movement in any direction and obstructing the inside against radially inward movement in any direction by confining a fluid within the tube.

In testimony whereof I aflix signature.

DANIEL BENSON REPLOGLE.

continuing the internal gas pressure during l the setting of the tube.

2. A method of bending and drying a moist fiber tube composed of cellulose pulp, which comprises closing the flexible tube gas tight, heating the closed tube sufliciently to generate gas pressure within the tube sufiicient to maintain the circularity of the tube during bending, bending said tube while maintaining said gas pressure, and drying the gas tight closed bent tube to cause it to set by continued application of heat, thereby continuing the internal gas pressure during the set ting of the tube.

3. A method such as herein described, which comprises bending a straight moist tube into the desired curvature while causing yielding outward fluid pressure to be exerted uniformly against the internal surface of such tube by heating and thus expanding the fluid therein, and then removing the moisture from said tube while it is subjected to such pressure.

4. A method of bending a moist fiber tube which comprises subjecting the tube to bend-

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