Viscous Liquid Dispenser

Abstract

A viscous liquid dispenser suitable for dispensing the contents of collapsible tubes comprising a reservoir adapted to hold a viscous liquid, a length of elastic tubing connected at the upstream end thereof to said reservoir and having a high modulus of resilience, a wall means spanning at least a portion of the length of said elastic tubing and positioned adjacent thereto, a lever moveable with respect to said elastic tubing wherein both arms of said lever may be moved to wedge a portion of said elastic tubing against said wall means, the upstream portion of said moveable lever pressing said elastic tubing against said wall means before the downstream portion of said moveable lever presses said elastic tubing against said wall means to force said viscous liquid in the downstream direction where it is expelled from the oriface at the downstream end of said length of elastic tubing, and a closure means positioned adjacent said elastic tubing and above said downstream orifice to prevent viscous liquid from leaking from said orifice when said device is not in use and to prevent air from entering said elastic tubing after the expelling stroke of said lever so that additional viscous liquid is drawn by suction into said elastic tubing, said closure means being overridden by the movement of said viscous liquid during said expelling stroke.

Description

BACKGROUND OF THE INVENTION

This invention relates to a device for dispensing regulated quantities of a viscous liquid, and more particularly, relates to a device suitable for dispensing measured amounts to toothpaste from a collapsible metal tube.

In industrialized societies the distribution of viscous liquids in capped metal and plastic tubes is widespread. The contents range from grooming aids to medicinal preparations to household cleaning compounds to toothpaste. Virtually everyone has daily contact with the latter item unless he uses powdered toothpaste, as few people do, or unless he wears dentures, in which case he may well come in daily contact with a viscous denture adhesive dispensed from a collapsible metal tube.

The widespread use of these dispensing tubes has resulted in considerable engineering effort being expended in controlling their discharge characteristics, research which is not always conducted in favor of the consumer. For example, by controlling the diameter of the orifice the manufacturer may exert a subtle control over the amount of his product used per dose. The thickness of the walls of the dispensing tube and the shape of the tube itself can be varied to influence the amount of material left in the tube when it is discarded. For example, a heavy shoulder in the vicinity of the orifice can result in the failure of the average user to fully expel the material stored in the vicinity of the shoulder. Further, the properties of the viscous liquid itself can be controlled so that there is a greater tendency for a thick irregular film of the material to adhere to the inside of the tube, thereby increasing the waste factor and the ultimate profitability of the product to the manufacturer.

In the past, attempts have been made on behalf of the user to allow him to completely expel the viscous liquid from metal dispensing tubes. The simplist and most widespread device is the windup key which is inserted over the sealed end of the dispensing tube and turned as needed to insure that the toothpaste is completely dispensed from the tube. Such windup keys are currently in use but have not achieved widespread acceptance because they are easily lost or destroyed, they project from the tube and make it unwieldy and, although they will effectively expel most of the viscous liquid from the tube, they do not eliminate the annoying requirement of screwing and unscrewing the cap of the tube. Further, they are not capable of expelling the last increment of viscous liquid from tubes that have heavy shoulders near the orifice. They also either require the user to undertake a separate windup operation or require a two-hand dispensing operation so that the object, e.g., a toothbrush, on which the viscous liquid is dispensed cannot readily be held in the hand of the user.

Still more complicated dispensing devices have been devised to dispense viscous liquids from bulk sources and from collapsible metal tubes. These have received little acceptance because of their complex construction or because they are difficult to operate. One variety of dispensing devices essentially holds a collapsible metal tube in a fixed upright position and applies external pressure to force the contents of the tube out of the uncapped opening. These devices generally employ intricate spring, lever, or gear works to generate the force which is applied to the exterior of the metal tubes. Due to their complexity they are susceptible to breakdown and degradation especially in high humidity environments such as bathrooms.

It is known that a combination of peristaltic action and suction can be used to dispense viscous liquid from collapsible tubes. However, no simple and efficient mechanism has been devised to practice the combined peristaltic-suction principle and to avoid the problems of air leaks and the time delay before a device can be reused. In U.S. Pat. No. 2,113,022, issued to Hefti, a spring driven arm with an attached roller is disclosed which peristaltically squeezes viscous liquid from a resilient tubing. The tubing eventually refills with viscous liquid as a result of the resiliency of the tube creating suction (a partial vacuum therein. The arm is pushed upwardly and away from the resilient tubing so as not to squeeze viscous liquid back into the collapsible tube. To keep the inflow of air at a minimum it is necessary to hold the arm in the lower position for a period of time until the resilient tubing has refilled. One hand of the operator is required to operate the device and the other hand of the operator must be used to hold the viscous liquid receiver, e.g., a toothbrush, in an appropriate position to accept the viscous liquid.

It is therefore an object of this invention to provide a simple and efficient viscous liquid dispensing device which employs the peristaltic-suction principle to dispense viscous liquids.

It is also an object of this invention to provide a viscous liquid dispensing device which can be easily actuated by the object on which the viscous liquid is dispensed, a feature that is highly useful for paraplegics and for persons who wish to free one hand for other tasks.

It is a further object of this invention to provide a viscous liquid dispensing device which is capable of more completely dispensing the contents of collapsible metal tubes.

It is another object of this invention to provide a viscous liquid dispenser capable of dispensing viscous liquid from collapsible tubes having varying cap diameter and thread characteristics.

It is a still further object of this invention to provide a viscous liquid dispensing device employing the peristaltic-suction principle which does not have any built-in significant time delay before it can be reused and which will discharge viscous liquids without air bubbles therein.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate comprehension of the present invention reference may be had to the accompanying drawings which are hereby incorporated in and made a part of this specification and in which:

FIG. 1 is a perspective view of one embodiment of the present invention illustrating the dispenser housing and, in phantom, a collapsible tube, a length of elastic tubing, lever means, wall means, and closure means.

FIG. 2a is a broken away side view of the lower portion of the dispensing device of FIG. 1 illustrating the ready mode of the dispensing device.

FIG. 2b is a broken away side view of the lower portion of the dispensing device of FIG. 1 illustrating the active mode of the viscous liquid dispensing device, i.e., the position of the lever means at the end of an expelling stroke.

FIG. 3 is a detailed section view of the orifice of the dispensing device of FIG. 2b.

FIG. 4 is a broken away end view of the lower portion of the viscous liquid dispensing device of FIG. 2b.

FIG. 5 is a sectioned side view of a guide means for collapsible tubes.

FIG. 6 is a side view of an alternative embodiment of the viscous liquid dispensing device of the present invention. of the viscous liquid dispensing device of FIGS. 1, 2a, 2b, and 4.

SUMMARY OF THE INVENTION

Within a dispenser housing, a reservoir containing a supply of viscous liquid is connected to one end (defined as the upstream end) of a length of elastic tubing having a high modulus of resilience. A wall means is mounted within the housing adjacent the elastic tubing and spans at least a portion of the length of the elastic tubing. A moveable lever means is mounted adjacent said elastic tubing opposite the location of said wall means. The fulcrum of the moveable lever means is initially at the downstream end of the moveable lever means so that the moveable lever means forms an inclined surface which moves to press said elastic tubing against said wall means. The inclination is such that the upstream lever arm presses the elastic tubing against the wall means before the downstream lever arm. When the upstream end of the moveable lever means has pushed inwardly as far as possible, the fulcrum shifts to the upstream end and the downstream end of the moveable lever means begins to move inwardly. This peristaltically forces the viscous liquid inside the tubing in the downstream direction. In the preferred embodiment a nub projects from the end of upstream lever arm to prevent any flow of viscous liquid in the upstream direction.

After the lever means has been forced to its furthest reach and viscous liquid dispensed from the orifice at the downstream end of the length of elastic tubing the motive force is removed so that the elastic tubing will return to its original position. The movement of the elastic tubing returns the moveable lever back to its initial position. At the same time, the return of the inner walls of the elastic tubing to their original cylindrical configuration creates a vacuum suction which draws additional viscous liquid into the tubing. A positive closure means adjacent the elastic tubing and located above the orifice at the downstream end thereof prevents air from being drawn into the tubing.

In practice, the present invention will be utilized by attaching it to a wall or embodied in a fixture such as a medicine cabinet so the viscous liquid can conveniently be dispensed.

The viscous liquid dispensing device of the present invention utilizes a two step method to efficiently dispense viscous liquids. A moveable lever means is used as a wedge to force the elastic tubing against the wall means so that a regulated amount of viscous liquid is dispensed from the orifice of the tubing. Then, the potential energy which is stored in the deformed elastic tubing due to its high modulus of resilience forces the lever means to return to its initial position and generate a vacuum which causes additional viscous liquid to be drawn into the elastic tubing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the embodiment shown in FIG. 1 it can be seen that a collapsible tube 11 is contained within dispenser housing 7 which consists of removable cover 10 which is insertable within base 9, and mechanism frame 8. Base 9 is integrally connected to mechanism frame 8 within which the dispensing mechanism is mounted. Dispensing lever 14 depends below mechanism frame 8 to permit an object, e.g., a toothbrush, to be inserted in concave recess 17 so that dispensing lever 14 may be pushed rearwardly to actuate the dispensing mechanism whereby a regulated amount of the viscous liquid is dispensed.

The operation of the dispensing mechanism of the embodiment of FIG. 1 may be seen by examining FIGS. 2a, 2b, and 7. In FIG. 2a the dispensing mechanism is in its ready mode. If the dispensing device has previously been used properly the interior of elastic tubing 18 will be completely filled with the viscous liquid. Thus, when arm 12 of dispensing lever 14 is moved rearwardly dispensing lever 14 pivots about fulcrum 6 which is permanently affixed to mechanism frame 8 so that arm 15 comes in contact with and applies force to the moveable lever 50 which abuts elastic tubing 18.

As is evident from FIG. 7 the fulcrum of moveable lever 50 will initially be at pin 54 after the up stream portion of moveable lever 50 (shown as the preferred protruding nub 56) is forced fully against the elastic tubing 18 the fulcrum of moveable lever 50 will shift and the protruding nub 56 will become the fulcrum. Then, the downstream portion of moveable lever 50 will be forced into elastic tubing 18. As dispensing lever 14 is actuated by force on arm 12 the point of contact between arm 15 and shim 53 will move along shim 53 towards the center of moveable lever 50. It will move only a slight distance, however. Thus, moveable lever 50 will move in two stages in an inclined attitude with respect to elastic tubing 18 so that the upstream portion of moveable lever 50 (lever arm 51) will be pressed against elastic tubing 18 first and then downstream portion of moveable lever 50 (lever arm 52) will be pressed against elastic tubing 18. This latter movement is facilitated by the movement of pin 54 within the slots formed by edges 55 in dispensing frame 8. The result of the two stage movement of moveable lever 50 is that elastic tubing 18 is wedged against wall means 16 which is affixed to the sides of mechanism frame 8. As a result the viscous liquid enclosed within elastic tubing 18 between the end of upstream lever arm 51 and the end of downstream lever arm 52 is forced in the downstream direction. A protruding nub 56 is affixed in the preferred embodiment to the end of the upstream lever arm to serve as a fulcrum for the second stage movement of moveable lever 50 and to prevent the viscous liquid from flowing in the upstream direction. The nub is preferably blunted so elastic tubing 18 is not subject to inordinate wear. It has been found that the dispensing mechanism of FIG. 7 is so efficient that within a few seconds after the force on arm 12 is removed the elastic tubing has nearly returned to its original shape and the dispensing device can be used again.

The preferred parameters of length of elastic tubing 18 can be discussed by reference to FIG. 2b. The upstream end of elastic tubing 18 is affixed to a collapsible tube adapter 19 slightly above the point of contact with the upstream end of moveable lever 50. It is desireable to minimize the distance between adapter 19 and the upstream end of moveable lever 50 so that energy is not wasted in transporting additional viscous liquid through long lengths of elastic tubing; yet, the distance cannot be so short that elastic tubing 18 ruptures from the deformation introduced by the wedge action of the upstream end of moveable lever arm 50.

The closure means of this embodiment is shown to be a curved strip of spring steel 20 which is attached to mechanism frame 8 and which presses elastic tubing 18 against lower wall means 27. The tension must be adjusted to be great enough to prevent air from entering the orifice at the downstream end of the elastic tubing after the expelling stroke and weak enough to be overcome by the downstream motion of the toothpaste or other viscous liquid. The closure means must be positioned close enough to the downstream end of moveable lever 50 so that the downwardly moving viscous liquid is not accomodated by an increase in the inner diameter of the portion of elastic tubing 18 located between the downstream end of the moveable lever and the closure means. The downwardly moving viscous liquid should open the normally closed closure means. Yet the closure means should not be so close to the end of the downstream lever arm so that one interferes with the operation of the other. With the particular closure device described above it has been found that virtually no air bubbles enter the stream of viscous liquid. Alternative closure means include an expandable rubber gromet surrounding the elastic tubing 18 and having an inner diameter less than the outer diameter of elastic tubing 18.

The arrangement of the elements of the dispensing mechanism of FIG. 1 can be visualized by reference to FIG. 4. Spring 20 terminates in cylindrical stub 26 which presses against elastic tubing 18. Wall means 16 spans a portion of the length of elastic tubing 18 and serves as one side of a wedge (the moveable lever serving as the other).

It has been found that the dispensing device of the present invention causes viscous liquid to flow first from the larger end of a collapsible tube (the end nearest the elastic tubing). If no pressure is exerted on the exterior of the collapsible tube the larger end will empty with flow characteristics approximating those of cylindrical viscous flow while the small end will gradually begin to empty with flow characteristics approximating laminar flow. The net result is that the larger end will empty nearly completely but the small end will buckle in along the center line (since the tube is most susceptable to buckling at the center and the forces of molecular attraction do not cancel out in that region) and ribbons of viscous liquid are left along the outside edges. To obviate this problem, in one embodiment, resilient guide strips 41, shown in FIG. 5, are provided to give the sides of the collapsible tube a gentle pressure which does not significantly aid in forcing viscous liquid from the tube but only establishes the viscous flow as having flow characteristics approximating laminar flow. Thus, the middle region of the tube, as defined by the mid region of the guide strips, buckles in along the whole length of the tube and the ribbons of viscous liquid on either side are drawn out by the suction provided by the dispensing mechanism. In another embodiment spring loaded guide strips are used. With guide strips it has been found that collapsible metal tubes containing viscous liquid are emptied so completely that the metal tube collapses into a thin strip.

Regulation of the quantity of viscous liquid which is dispensed is achieved by choosing elastic tubing of a desired inner diameter and selecting the total length and angle of inclination of the moveable lever means. The shape of the dose, e.g., its diameter as opposed to its length, can be varied by placing a specially shaped conduit, e.g., a triangular or star shaped conduit, at the downstream end of the plastic tubing. In FIG. 3 cylindrical conduit 22 is shown to be seated in orifice housing 23 beyond the downstream end of elastic tubing 18. The inner diameter of cylindrical conduit 22 will control the diameter of the dose. If desired, conduits of various shapes could be supplied with a given dispensing device.

A simple alternative embodiment of the viscous liquid dispensing device of the present invention is shown in FIG. 6. A collapsible metal tube of toothpaste 46 is screwed into adapter 47 which in turn screwed into threaded seat 48 of dispenser housing 30. The internal thread characteristics of adapter 47 may be varied to accomodate any commercially available collapsible metal tubes. A simple lever 34 is mounted within housing 30 by means of attached pins 39 which ride within slots defined by edges 38 formed in the sides of housing 30. The fulcrum of simple lever 34 is determined by the position of integral shaft 33 which is located nearer the upstream end (defined as the end nearest the viscous liquid supply) than the downstream end so that upstream lever arm 35 is shorter than downstream lever arm 36. As a result, when toothbrush 37 is forced against toothbrush receiving lip 32 of integral shaft 33 the simple lever 34 presses into elastic tubing 31 in an inclined attitude and wedges elastic tubing 31 against inner wall 40 of housing 30. The upstream lever arm precedes the downstream lever arm so that toothpaste is forced through elastic tubing 31 in the downstream direction and is expelled at the orifice 42 on the bristles of toothbrush 37. In the ready mode, i.e., the inactive mode shown in FIG. 6, plunger 49 would constrict elastic tubing 31 by pressing it against wall means 45 which is permanently affixed to the sides of housing 30. But, in the active mode, when simple lever 34 is pressed against elastic tubing 31 plunger 40 is moved away from elastic tubing 31 to permit the downstream flow described above.

While several specific embodiments have been enumerated in this specification the present invention is intended to be limited solely by the scope and spirit of the appended claims.

Claims

I claim:

1. In a viscous liquid dispensing device the combination comprising,

a length of elastic tubing having a high modulus of resilience;

a reservoir adapted to contain a viscous liquid and connected to the upstream end of said length of elastic tubing;

wall means spanning at least a portion of the length of said elastic tubing and positioned adjacent thereto;

wedge means moveable with respect to said elastic tubing and positioned adjacent thereto and on the opposite side of said tubing from said wall means so that said wedge means may be moved to wedge a portion of said elastic tubing against said wall means, the upstream portion of said wedge means pressing said elastic tubing against said wall means before the downstream portion of said wedge means to force said viscous liquid in the downstream direction to be expelled from the orifice at the downstream end of said length of elastic tubing;

and closure means positioned adjacent said elastic tubing and above the orifice at the downstream end thereof to prevent said viscous liquid from leaking from said orifice at said downstream end of said elastic tubing when said device is not in use and to prevent air from entering said orifice after the expelling stroke of said wedge means when said elastic tubing is returning to its natural shape and drawing additional viscous liquid, said closure means being overridden by the movement of said viscous liquid during the expelling stroke of said wedge means to permit the discharge of viscous liquid from said orifice.

2. The viscous liquid dispensing device of claim 1 wherein said wedge means is actuated by the movement of the object on which said viscous liquid is dispensed.

3. The viscous liquid dispensing device of claim 2 in combination with a second lever having a fixed fulcrum, wherein one arm of said second lever may be actuated by the object on which the viscous liquid is dispensed and wherein the other arm of said second lever abuts said wedge means so that said object may effect the dispensing of viscous liquid.

4. The viscous liquid dispensing device of claim 3 wherein said reservoir is a collapsible metal tube.

5. The viscous liquid dispensing device of claim 4 wherein said object is a toothbrush.

6. The viscous liquid dispensing device of claim 3 wherein a protruding nub is affixed to the upstream end of said wedge means to prevent backward flow of viscous liquid when said wedge means is wedged against said elastic tubing.

7. The viscous liquid dispensing device of claim 6 wherein said tube is held between spring loaded guide strips to assist said tube to discharge uniformly.

8. The viscous liquid dispensing device of claim 6 wherein said reservoir is a metal toothpaste tube held between resilient guide strips whose inherent spring tension assists said tube to discharge uniformly.

9. The viscous liquid dispensing device of claim 6 wherein said closure means is a spring having a cylindrical stub on the end thereof to wedge said elastic tubing against a secong wall means adjacent the orifice at the downstream end of said elastic tubing.

10. In a viscous liquid dispensing device having a viscous liquid reservoir, a length of elastic tubing attached to said reservoir and a closure means positioned adjacent the downstream end of said length of elastic tubing, the improvement comprising positioning a wedge means adjacent said length of elastic tubing on one side thereof and positioning a wall means on the other side thereof so that said wedge means may be moved to press said tubing against said wall means, one side of said wedge means pushing simultaneously into a discrete length of said tubing with the upstream end of said side of said wedge means pressing slightly ahead of the downstream end thereof so that a measured amount of viscous liquid is expelled through said closure means.