US 3285473 A
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Description (OCR text may contain errors)
Nov. 15, 1 1-1. E. .1. FUHRMANN 3,285,473
TUBE FOR RECEIVING PASTY SUBSTANCES Filed Nov. 2, 1964 H1 Ill Fig.7 Fig) I I Fig.3
INVENTOR. Hen/K10! psrJSmw lm/M United States Patent 3,285 473 TUBE FOR RECEIVING PASTY SUBSTANCES Heinrich Ernst Johann Fuhrmann, Eschersheimer Landstrasse 68, Frankfurt am Main, Germany Filed Nov. 2, 1964, Ser. No. 408,067 6 Claims. (Cl. 222-107) The present invention relates to a tube for receiving pasty substances, such as greases, color pastes, ointments, and the like. More specifically, this invention is directed to a tube of the folded wall or bellows type which is emptied either by application of atmospheric pressure in cooperation with a partial vacuum which becomes effectice at the tube outlet opening, or by a gaseous medium under pressure, such as compressed air.
Very frequently, tubes of the above-noted type cannot properly be emptied when they are used in emptying devices in which the contents of the tube are not squeezed out by some mechanical means, such as pistons or the like. By proper emptying is meant here that the tube can be completely emptied and that during the emptying process, which is initiated arid continued in response to a partial vacuum at the tube outlet, no constrictions are formed in the tube which would impair the proper emptying of the tube. In conventional tubes of the folded wall or bellows type such constrictions may occur, if pressure is applied to the outer tube surfaces of a partly filled tube. In such a case the tube interior adjacent the tube outlet would be reduced in area, since the substance with which the tube is filled flows off first from that region of the tube which is adjacent the outlet opening. As a result, the substance in the narrowed areas of the tube cannot flow off any longer. As the emptying process continues, the folds of the tube progressively approach each other, until they lie closely side by side. Since the walls of the tube have a certain thickness, the wall thicknesses of the folds add up so that the tube will have a certain height even when its folds lie closely side by side. Thus, if it is assumed that there are twenty folds and that the Wall thickness is about 0.04 in. then the tube still would have a height of about 1.6 in., when collapsed, That is to say, even when the tube folds would lie closely side by side, there would be left a cylindrical interior space which would be enclosed by the collapsed folds and could not be emptied anymore.
Accordingly, it is a primary object of this invention to provide a tube of the folded wall type which can be properly and completely emptied without the aid of me-. chanical means such as pistons or the like.
Another object of the invention is to provide a tube in which no constrictions will occur, as the tube is emptied by applying under pressure a gaseous medium to its surfaces.
Still another object of the invention is to provide a tube in which the thickness of the tube walls at the end remote from the tube outlet opening is so selected that this portion of the tube can be turned upside down into the cylindrioal interior space of the tube which is left over after the folds are collapsed.
The tube of the invention has ring-shaped or helical folds and exhibits a radial resistance to deformation, which progressively increases in the direction of the tube outlet opening. This radially effective resistance to deformation is brought about by either progressively increasing the thickness of the tube walls in the direction of the tube outlet opening or by progressively reducing the spacing of adjacent folds in the direction of the tube outlet opening or by a combination of both.
Thus the tube of the invention has at its outlet end a larger wall tln'ckness or more closely spaced folds or both so that this tube portion is particularly resistant to 3,285,473 Patented Nov. 15, 1966 ice external pressure, thereby preventing any early formation of constrictions.
On the other hand, the tube bottom and the adjacent portions of the tube Walls are less resistant to deformation, because the wall thickness progressively decreases in the direction of the tube bottom, or the spacing of adjacent folds becomes progressively larger or both, so that the less resistant bottom portion of the tube can be turned upside down into the above-noted remaining cylindrical interior space of the tube at the end of the emptying operation.
Further features and advantages of the tube of the invention will become apparent from the following detailed description, when read in conjunction with the drawings, in which several embodiments of the invention are illustrated.
In the drawings FIGURE 1 is a cross-sectional view of a tube emptying device with an inserted tube of the invention, the lefthand tube portion being shown provided with a folded wall of varying thickness and the right-hand tube portion being shown provided with differently spaced folds;
FIGURE 2 is a cross-sectional view of the device of FIG. 1 with a partly emptied tube, and 1 FIGURE 3 shows an emptying device with a partly emptied tube and means for preventing expansion of the emptied tube.
Referring now more particularly to FIG. 1, there is shown the conventional emptying device which comprises substantially the following parts: An enclosure 1 having an opening 2 through which a collapsidble or folding tube 3 may be inserted. Enclosure 1 is made from rigid material and supported from a hollow elongated portion 4 which accommodates a low-pressure cylinder 5 and a high-pressure cylinder 8 which can be fitted over a stationary piston and sealed by a ball valve member 7. Upon forcing the emptying device with its outlet end 9 over a lubrication nipple (not shown), cylinder 8 is caused to slip over piston member 6. Upon exerting no pressure on the device in this position any longer, a spring 10 urges cylinder 8 away from piston member 6, thereby causing negative pressures to be generated in cylinders 5 and 8. These negative pressures have a cumulative effect on the tube opening 11 so that the atmospheric pressure may become effective through aperture 2 thereby impinging upon the entire tube surface area. This causes the grease or any other substance with which thetube may be loaded, to flow from tube region 12 adjacent tube opening 11 through the latter into cylinder 5. Upon application of the next stroke this portion of the tube contents is forced by piston 6 into the lubrication nipple. Of course it is also possible to provide for instance a pressure line through which a gaseous medium may enter enclosure 1 through opening 2. If the walls of tube 3 had a uniform thickness throughout, or, if the folds were of equal size, then it might be possible that the tube is radially narrowed or constricted in outlet region 12 from which the grease would flow off first. As a result, the supply of grease from the remaining tube portion 13 would be impeded. To eliminate this disadvantage, tube walls 14 are relatively thick adjacent the outlet region, whence they gradually decrease in thickness in the direction of tube bottom 15, as shown in FIG. 1 at the left. Alternatively, the folds in the tube walls of the lower or outlet zone of the tube may be spaced more closely side by side than the folds adjacent the bottom of the tube. Either arrangement has the advantage of providing a maximum radial resistance to deformations of the lower or outlet portion of the tube, Naturally, the two walls arrangements can be combined, if desired, as shown in FIG. 3.
FIG. 2 shows tube 3 almost emptied. That is to say,
the tube has been forced together so that its folds are spaced closely side by side. In this state, a remaining cylindrical space 16 is enclosed by the folded walls of the contracted tube. Normally, space 16 can hardly, if at all, be emptied. However, since the tube walls are thinnest in tube region 15, the tube bottom and part of the adjacent folds may be urged into the remaining cylindrical space 16, as indicated by the dash-dotted line in FIG. 2, thereby squeezing any remaining grease out of space 16.
To prevent tube 3 from being unfolded or expanded in enclosure 1 after it is empty, as would be the case, if for instance ball valve member 7 were leaky, the embodiment of the tube shown in FIG. 3 is used in combination with a so-called follower piston 17. This piston must have an aperture 18 to permit the tube to be completely emptied, as described in conjunction with FIG. 2. As tube 3 contracts, piston 17 follows tube bottom 15 steadily. Small springloaded balls 19 are provided in enclosure 1 which are urged against the walls of enclosure 1 thereby producing a clamping effect which prevents piston 17 from returning to its starting position. It should be understood that also other suitable means may be used as clamping elements,'it being only necessary that such elements provide the desired clamping effect. The piston may be of the same material as the tube. Such a material may be a polymer plastic material such as plasticized polyvinyl chloride, polyethylene, etc. In outlet zone 12 the folded walls of the tube are about .010 to .020 in. thick, whereas the thickness of tube bottom 15 and of the tube walls adjacent bottom 15 may range from about .004 to about .008 in.
While the present invention has been described hereinbefore in connection with lubricating sets which are loaded with lubricant-filled cartridges or tubes, it will be understood that this invention may be practised in all cases where cartridges or tubes filled with pasty substances have to be inserted into emptying devices. Accordingly, the scope of this invention is to be governed by the language of the following claims construed in the light of the foregoing description of this invention.
What is claimed and desired to secure by Letters Patent is:
1. A tube having folded wall surfaces, comprising a closed bottom portion, a top portion having an outlet opening therein, and a tubular intermediate portion extending between said bottom portion and said top portion, said intermediate portion having folds and deformationresistant means, the resistance offered by said deformation-resistant means to radial deformation by pressure being at its maximum adjacent said top portion and at its minimum adjacent said bottom portion, said bottom and top portions as well as said folded intermediate portion being walls, the walls forming said bottom portion 4 and the bottom end of said folded intermediate portion being thinner than the walls forming the top end of said folded intermediate portion, the thinner walls of said bottom portion and said bottom end of said folded intermediate portion forming a tube portion extending upside down into the interior of said tube upon application of pressure on said thinner walls.
2. The tube according to claim 1 wherein the walls of said folded intermediate portion are thick adjacent said top portion and are progressively reduced in thickness in the direction of said bottom portion such that said bottom portion is at least as thin as said bottom end of said folded intermediate portion.
3. The tube according to claim 2 wherein the wall thickness of said top end of said folded intermediate portion is about .010 to about .020 in. and the wall thickness of said bottom end of said intermediate portion is about .004 to about .008 in.
4. The tube according to claim 1 wherein adjacent folds of said intermediate portion are spaced more closely at said top end than at said bottom end of said intermediate portion, the arrangement being such that the spacing of said adjacent folds progressively increases in the direction of said bottom end.
5. The tube according to claim 1 wherein said resistances to deformation are effected by a combination of the wall thickness of said intermediate portion with the folds of said intermediate portion, the wall thickness of said intermediate portion progressively decreasing from said top end in the direction of said bottom end, adja cent ones of said folds being spaced more closely at said top end than at said bottom end, the arrangement being such that the spacing of adjacent ones of said folds progressively increases in the direction of said bottom end throughout the length of said intermediate portion.
6. The tube according to claim 5 wherein the wall thickness of said top end of said folded intermediate portion is about .010 to about .020 in. and the wall thickness of said bottom end of said intermediate portion is about .004 to about .008 in.
References Cited by the Examiner FOREIGN PATENTS 1/1938 Great Britain. 4/ 1964 Great Britain.
OTHER REFERENCES German application 1,118,399, November 1961.