US2774518A - Moldable cone bellows - Google Patents

Description

Dec. 18, 1956 N. GREENE 2,774,518

MOLDABLE CONE BELLOWS Filed June 2, 1953 2 Sheets-Sheet l INVENTOR. MOAZMA/V (fkEEA/ Dec. 18, 1956 N. GREENE 2,774,518

MOLDABLE CONE BELLOWS Filed June 2, 1953 2 Sheets-Sheet 2 i .lZ.

INVEN TOR. ,vazmw GZEEA/E United States PatentO MOLDABLE CONE BELLOWS Norman Greene, New York, N. Y.

Application June 2, 1953, Serial No. 359,124

16 Claims. (Cl. 222209) This invention relates to bellows for squeeze containers, and more particularly to a conical (or pyramidal) bellows useable as part of a container.

The primary object of the present invention is to generally improve flexible bellows, and containers using the same. A more particular object is to provide a bellows which is so contoured and constructed that it may be molded between the halves of a simple two-part mold which opens in a direction axially of the bellows. Still another object is to provide a bellows which, although readily deformable is characterized by a strong restoring force which dependably brings the same back to initial position. With these objects in view I have devised a compressible bellows shaped to form a series of concentric steps converging upwardly, with each of said steps having what may, for convenience, be termed a generally upright wall and a generally horizontal wall, the said walls preferably being disposed within angular limits later defined. p M I A further object of the invention is to devise a bellows which may be used with containers intended to carry and dispense food products, drug products, and cosmetics. Plastic molding materials which have come into wide use in recent years for this purpose are polyethylene and polyisobutylene and mixtures of the two. These plastics are flexible, but experience negligible, if any, compression or stretch. In this respect they are quite different from a flexible material such as rubber, for example. This characteristic may occasion difiiculty when using a stepped bellows of the type so far described because when the bellows is depressed the steps tend to turn inward, resulting in a reduction in the circumferential length of the steps.

A further object of the present invention is to overcome this difiiculty, which I do by providing the bellows with radial grooves. These grooves ascend with the steps, and are preferably deeper than the individual steps. When the bellows is depressed the sides of the grooves come toin accordance with a further feature and object of the present invention, the lower ends of the grooves terminate in a generally upright wall, the arrangement being such as to permit the lower ends of the grooves to yield outwardly when the bellows is compressed.

To accomplish the foregoing general objects, and other i "ice Fig. 3 is a side elevation of the bellows;

Figs. 4 and 5 are fragmentary sections through the bellows and are explanatory of the operation of the same;

Fig. 6 is a fragmentary plan view of the bellows in depressed or squeezed condition;

Fig. 7 is a vertical section through a modified form of bellows having an integral threaded ring;

Fig. 8 is a partially sectioned elevation of a modified container in which the bellows is secured to the container with a snap fit;

Fig. 9 is a partially sectioned elevation of a modified container in which the side wall of the container is molded integrally with the bellows;

Fig. 10 is a plan view of a modified bellows in which the converging steps are generally pyramidal rather than conical;

Fig. 11 illustrates the range and preferred angle for the generally vertical walls of the steps;

Fig. 12 illustrates the range and preferred angle for the generally horizontal walls of the steps;

Fig. 13 shows overstressing of the bellows; and

Fig. 14 shows a modification of the bellows.

Referring to the drawing, and more particularly to Figs. 1, 2 and 3, the bellows there illustrated has a series of concentric steps 12, 14 and 16 which converge upwardly. Each of'the steps has what may, for convenience, be called a generally upright wall 18, and a generally horizontal wall 20.

Referring to Fig. 11, which corresponds to the lower left end of the bellows section in Fig. 1, it may be explained that the generally upright wall may be disposed at an angle in a range of from to considered in clockwise direction as shown on the drawing. The preferred angle is very close to vertical, and is slightly greater than 90, say 92, in order to facilitate the molding operation by providing taper or draft which helps release the bellows from the mold.

The generally horizontal wall is disposed at an angle of from 0 to 45 below horizontal, as shown by the range in Fig. 12 of the drawing, and it is preferably at an angle of from 10 to 20 below horizontal, this being the shaded area in Fig. 12.

The bellows may be made of metal, rubber, or many of the known plastics such as cellulose acetate, but when used with dispensing containers intended to carry food products, drug products, and cosmetics, the bellows is preferably molded out of polyethylene, polyisobutylene, or mixtures of the two. This plastic is flexible, but is virtually non-compressible and non-stretchable. When the bellows is compressed or squeezed downward, as shown by the change from Fig. 4 to Fig. 5 of the drawing, the steps tend to fold or roll inward, as shown by the change in position of the parts 12, 14 and 16. This is accompanied by a decrease in diameter and circumferential dimension for each step. In order to accommodate this change without excessively stressing the material, I provide the bellows with radial grooves, shown at 22, 24, 26, 28 in Fig. 2. Thesegrooves ascend with the steps, and they are preferably deeper than the individual steps, as will be seen from inspection of Figs. 3 and 4. The sides of the groove may come together, that is, the grooves may narrow, as will be seen by comparison of the grooves 22 and 28 in Figs..2 and 6. Thus the grooves readily accommodate the reduction in peripheral length of the steps when the bellows is pressed.

By referring toFig. 3 it will be seen that the lower end of groove 26 terminates in the generally upright wall 18. This is done in order to more readily accommodate the outwardmovernent of the grooye portion itself. Thus by comparing Figs. 4 and 5 it will be seen that when the bellows is pressed downward the groove 28 moves from the angular position shown in Fig. 4 to the substantially horizontal position shown in Fig. 5, and this results in an outward movement which is accommodated by an outward bulging or ballooning of the wall 18. The net etfect of this construction is that the bellows is readily pushed downward without excessively stressing the material and yet is returned to initial position with a good restoring force.

Reverting now to Fig. 1, the bellows there shown is used to close the top of an open-topped jar or container 30. This may be a rigid glass container of conventional type. It is provided with a threaded neck portion 32. The bellows has a flange or horizontal peripheral portion 34 of suitable diameter to rest on top of the neck portion 32 of the jar. The bellows is secured in position by means of a threaded ring 36, which may be made of metal. This ring is threaded at 38 to mate with the threaded part 32 of the jar, and it has a flange portion 40 which overlies the flange 34 of the bellows. No additional gasket is needed because the material of the bellows is somewhat yieldable and, itself, forms a satisfactory gasket.

The central portion of the bellows is preferably solid and acts as a raised knob or stud 42 which facilitates depression of the bellows. It is provided with a blind vertical hole 44 which receives the upper end of a pump tube 46, the lower end of which tube preferably reaches the bottom of the container. The stud portion 42 further has a blind radial hole 48 which communicates with the vertical hole 44 and which receives a discharge tube or spout 50. It will be evident that by depressing the bellows some of the content of the jar 30 is delivered through the spout 50. The stud 42 is preferably provided with a vent hole 52. The lower portion 54 of the vent hole may be of increased diameter in order to facilitate molding the same, but at least the upper part of the vent hole is of minute bore or capillary dimension. The main purpose of the vent hole is to take care of expansion of air above the liquid content of the jar resulting from temperature change, typically on removing the container from a refrigerator to the table.

It will be noted that the entire bellows structure, including the stud 4-2, may be molded between the halves of a simple two-part mold, excepting only the radial hole 48 for the spout 59. A retractable core is preferably provided in the mold for this purpose, although it is possible under more limited production conditions to form one or more of the holes in other ways, as by drilling in a suitable fixture or jig. The stud portion 42 is preferably made solid or largely solid, as shown, despite the consumption of a small additional amount of the plastic molding material, because the preferred plastics are not susceptible of being joined by adhesive or solvent action, and it is therefore simple and economical to secure the tubes 46 and 50 by means of a force fit, the tubes being forced into the mating holes 44 and 48 formed in the relatively solid stud portion at the center of the bellows. It will be understood that the pump tube 46 and spout 50 have been omitted in the remaiinng figures of the drawing in order to simplify the same.

Fig. 7 shows a modified bellows top intended for use on a jar like that shown at 30 in Fig. 1. This modification differs in that the bellows, instead of terminating in the flat horizontal flange portion 69 (Fig. 7), is additionally formed with an integral cylindrical portion 62 which is internally threaded at 64 to mate with the threaded portion 32 (Fig. 1) of the jar. It will be understood that the threads 64 are relatively rounded and that the proportioning of the parts is such that the threads may be stripped from the ejector half of the die after the die has been opened. This procedure is already known in the molding of plastic materials, and is mentioned only to make it clear that the bellows is adapted for molding directly between two mold parts which separate in a direc tion axially of the bellows, despite the presence of the thread 64.

The form of the invention shown in Fig. 8 is generally similar to those already described, except that the bellows top, generally designated 70, is secured to the jar or container 72 with a snap fit. Specifically, the upper end or neck portion of the container is provided with a groove 74. The cylindrical part 76 of the bellows is provided with an inwardly directed lip or undercut 78 dimensioned to mate with the groove 74. The parts are suitably dimensioned and shaped to permit the same to be put together with the desired snap fit.

Fig. 9 shows a modified form of the invention in which the side wall 80 of the container is made of the same plastic and is molded integrally with the bellows 82. Thus the complete container is formed in a single molding operation, except for the bottom 84. The bottom may itself be molded and may be secured to the side wall 84 in any desired fashion as, for example, by fusing or welding the parts together by application of heat, or more simplyby means of a snap engagement, for which purpose the side wall 80 is thinned or necked slightly at the point 86.

As so far described the bellows has been assumed 'to be circular or conical, but other shapes may be employed, and Fig. 10 shows a modified bellows which is square or pyramidal. Thus referring to Fig. 10 it will be seen that the walls of the steps on each side are straight, as shown at 90, 92, 94, 96. The grooves or channels 98 are preferably disposed diagonally of the resulting square, and are mutually at right angles, as is clearly shown in the drawing. The central portion 100 is a solid stud or knob as previously described, and may be provided similarly with a vent hole and with intersecting blind holes, one vertical to receive a pump tube, and the other approximately horizontal to receive a discharge tube or spout.

The bellows terminates in a fiat area or flange 102, and this has been shown circular in Fig. 10 for use at the top of a cylindrical container, but it will be understood that the flange 102 might equally well be square for use on top of a square container. It will also be understood that the bellows of Fig. 10 may be provided with an internally threaded cylindrical portion as shown at 62, 64 in Fig. 7, or with a side wall portion arranged for a snap fit as indicated at 76, 78 in Fig. 8, or with an integral side wall as indicated at 80 in Fig. 9. The constructions of Figs. 8 and 9 are applicable to a square outline as Well as a circular outline. In that connection it will be understood that the bellows may be made in other shapes than square as, for example, rectangular, triangular, elliptical, etc.

Under some circumstances the bellows may be subjected to excessive stress. It may be pushed down an amount beyond that indicated in Fig. 5, thus bringing the parts to a position somewhat like that shown in Fig. 13. The same effect may be produced at one side only of the bellows by pushing it 'sidewardly instead of straight down. When the bellows is stressed excessively the bottom of the groove is subjected to a cross-tension or splitting force which tends to split the groove lengthwise along the bottom.

In bellows designed for purposes in which the bellows may be repeatedly subjected to overstress of this nature I prefer to make the groove with a cross-section resembling a W instead of a U. This is illustrated in the modification shown in Fig. 14 of the drawing. This view is the same as that shown in Fig. 3 already described, but in the present case the groove, generally designated 126, is reversely formed or upwardly convex along its bottom cen ter line, as shown at 128. The contour of the section may be called W but is preferably rounded, rather than sharp angled. It will be evident that with this corrugated or W cross-section, the bottom region of the groove is well adapted to expand sidewardly, and thus to accommodate the spreading tendency or cross-tension to which it is subjected when the bellows is compressed for a substan tial distance.

In Fig. 14 the dotted line 130 represents the bottom of the next step 132. It has been shown in order to 1l1ustrate a detail which is not essential, but which is preferred in practice, namely, the fact that the height of the raised center portion 128 preferably should not exceed the height of the line 130. This is merely for convenience in fabricating the die in which the bellows is molded, because it makes it possible to cut the steps in a lathe, without interference by the mold parts which correspond to the raised center part 128 of the channel.

Before closing this description it may be pointed out that the compressible bellows may be employed for purposes other than the pump action illustrated in Fig. 1. It may, for example, be used with a top having a spray hole, or with a conical nozzle such as is used on oil cans, or with a dispensing cup arrangement such as that shown in U. S. Patent No. 2,599,446.

The bellows works in the following manner. As pressure is applied there is a convergence of the steps of the bellows. In order to allow the diameter of each step to be reduced, they are divided by the ascending grooves, which fold in a direction at right angles to the steps, and thus permit the reduction by bending, rather than by compressing or stretching the material. Thus the minimum width of this ascending groove is determined as that which allows adequate space for the maximum convergence which occurs when the bellows is totally compressed. The number of these ascending grooves may range from one upward, it being a matter of design, affected by the type of material used, and the flexibility and rebound properties desired.

The ascending grooves themselves may act as ribs antagonistic to the compression of the bellows. This is overcome by ending the groove in a flexible area, namely, at a point well above the junction of the vertical portion of the bottom step and the flange, thus allowing this wall to balloon out at the point where the groove joins it. There may be less or more than the four grooves shown.

The ability to injection mold or stamp a bellows that allows this great degree of displacement olfers many advantages, due to its ease of manufacture and low cost, in a variety of fields and uses, where it may be employed as a dispensing mechanism for drugs, chemicals, foods and cosmetics in the packaging field, or mechanical uses where a tapered bellows may be applied.

In general, a pumping action at the top has the advantage of making the bellows useable with a convenventional glass jar, but even when the entire container is made of plastic it has an advantage compared to a squeezing action at the sides, for the latter tends to break the seal between the sides and the base.

The wall thickness of the bellows should be such as to allow ample flexibility, yet with suflicient rigidity to obtain a spring-back to the resting position. This wall thickness would vary with the flexibility of the particular plastic or molding material used.

If desired the ascending grooves of the bellows may be given a W instead of a U cross-section, thereby affording spreading at the bottom of the grooves, as well as contraction at the top of the grooves. This takes care of any difficulty which might otherwise arise from cross-tension or splitting at the bottom of the grooves.

It is believed that the construction and operation, as well as the advantages of my improved bellows, will be apparent from the foregoing detailed description. It will also be apparent that while I have shown and described my invention in several preferred forms, changes may be made in the structures shown without departing from the scope of the invention, as sought to be defined in the following claims. In the claims the reference to a generally upright wall and a generally horizontal wall is to be considered in a relative rather than an absolute sense, it being obvious that the bellows may be mounted in a vertical instead of a horizontal position, to be squeezed horizontally instead of vertically, or in any other desired po- 6 sition which may be convenient for the particular use intended.

I claim:

1.- A vertically compressible bellows comprising a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, said bellows having radial grooves ascending with the steps, and said grooves being deeper than the individual steps, said grooves narrowing to accommodate the reduction in peripheral length of the steps when the bellows is compressed, the lower end of each of said grooves terminating in an upright wall to yield outwardly when the bellows is compressed.

2. A moldable vertically compressible bellows comprising a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, said generally upright wall being disposed at an angle of from to with respect to the horizontal, said generally horizontal wall being disposed at an angle of from 0 to 45 below horizontal, and said bellows having radial grooves ascending with the steps, said grooves narrowing to accommodate the reduction in peripheral length of the steps when the bellows is compressed.

3. A moldable vertically compressible bellows comprising a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, said generally upright wall being disposed at an angle of from 90 to 135 with respect to the horizontal, said generally horizontal wall being disposed at an angle of from 0 to 45 below horizontal, and said bellows having radial grooves ascending with the steps, said grooves narrowing to accommodate the reduction in peripheral length of the steps when the bellows is compressed, the material being selected from the group consisting of polyethylene and polyisobutylene and mixtures of the two.

4. A moldable vertically compressible bellows comprising a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, said generally upright wall being disposed at an angle close to but slightly greater than 90 with respect to the horizontal, said generally horizontal wall being disposed at an angle of from 10 to 20 below horizontal, said bellows having radial grooves ascending with the steps, and said grooves being deeper than the individual steps, said grooves narrowing to accommodate the reduction in peripheral length of the steps when the bellows is compressed, and the lower end of each of said grooves terminating in an upright wall to yield outwardly when the bellows is compressed. I

5. A vertically compressible bellows comprising a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, and said bellows having radial grooves ascending with the steps, said grooves narrowing to accommodate the reduction in circumferential length of the steps when the bellows is compressed.

6. A bellows as defined in claim 5, in which the central portion is a raised knob or stud having a blind vertical hole for receiving the upper end of a pump tube, and having a blind radial hole communicating with said vertical hole for receiving the inner end of a discharge spout.

7. A bellows as defined in claim 5, in which the concentric steps are circular, and in which there are four radial grooves disposed mutually at right angles to one another when viewed in plan.

8. A bellows as defined in claim 5, in which the concentric steps form the four sides of a square, and in which there are four grooves disposed diagonally of the square and mutually at right angles to one another.

9. A bellows as defined in claim 5, in which the periphcry of the bellows is provided with a generally cylindrical fiange having an internal thread dimensioned to mate with the threaded neck of a jar or container on which the bellows is to be used.

10. A bellows as defined in claim 5, in which the peripheral portion of the bellows is provided with a cylindrical flange having an undercut dimensioned to be received with a snap fit over the upper edge of a jar or container with which the bellows is to be used.

11. A bellows as defined in claim 5, in which the peripher'y of the bellows projects downward for a substantial distance to form the cylindrical wall of a container, whereby the container and bellows are formed integrally except for the bottom of the container.

12. A bellows as defined in claim 5, in which the radial grooves have a cross-section somewhat resembling a W, in order to accommodate expansion at the bottom of the groove.

13.-A moldable vertically compressible bellows compris'ing a single body of material shaped to form a series of concentric steps converging upwardly, each step having a generally upright wall and a generally horizontal wall, said generally upright Wall being disposed at an angle close to but slightly greater than 90 with respect to the horizontal, said generally horizontal wall being disposed at an angle of from 10 to 20 below horizontal, said bellows having radial grooves ascending with the steps, and said grooves being deeper than the individual steps, said grooves narrowing to accommodate the reduction in peripheral length of the steps when the bellows is compressed, and the lower end of each of said grooves termimating in an upright wall to yield outwardly when the bellows is compressed, the material being selected from the group consisting of polyethylene and polyisobutylene and mixtures of the two.

14. A bellows as defined in claim 13, in which the radial grooves have a cross-section somewhat resembling a W, in order to accommodate expansion at the bottom of the groove.

15. A bellows as defined in claim 13, in which the central portion is a raised knob or stud having a blind vertical hole for receiving the upper end of a pump tube, and having a blind radial hole communicating with said vertical hole for receiving the inner end of a discharge spout, and having a minute vent hole.

16. A bellows as defined in claim 13, in which the concentric steps are circular, and in which there are four radial grooves disposed mutually at right angles to one another when viewed in plan, and in which the radial grooves have a cross-section somewhat resembling a W, in order to accommodate expansion at the bottom of the groove.

References Cited in the file of this patent UNITED STATES PATENTS 1,293,864 Morton Feb. 11, 1919 1,975,265 Fulenwider Oct. 2, 1934 2,275,666 Wilson Mar. 10, 1942 2,314,263 Witt Mar. 16-, 1943 2,680,477 Schira June 8, 1954 2,686,006 I-Iasselquist Aug. 10, 1954

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