US2982443A - Liquid and semi-solid dispensing gun and method of dispensing - Google Patents

Description

May 2, 1961 R. T. ELLIS LIQUID AND SEMI-SOLID DISPENSING GUN AND METHOD OF DISPENSING 2 Sheets-Sheet 1 Filed June 28, 1957 I Illlllll United States Patent.

LIQUID AND SEMI-SOLID DISPENSING GUN AND METHOD OF DISPENSING Roy '1. Ellis, 200 Haver Road, Dayton, Ohio Filed June 28, 1957, Ser. No. 668,631

6 Claims. (Cl. 222-1) The present invention relates to a liquid dispensing gun that can be used for dispensing free-flowing or relatively stifl semi-solid liquids.

v In guns of this general type heretofore made, the mechanism has usually been of the positive displacement type in which a certain amount of liquid is entrained within a" barrel and then is expelled out through a nozzle by an arrangement that produces relative movement between the barrel and a piston. The flow from the source or reservoir into the barrel is regulated by a check valve that permits inflow, but exludes reflow back into the reservoir. In like manner, the discharge flow from the barrel to the nozzle is controlled by a check valve that permits outflow from the barrel to the nozzle, but prevents reflow from the nozzle to the valve. This valve is controlled by a spring, and stops all bleed, such as from temperature, altitude or like changes. Operation of the piston is often by a handle, and the present invention is particularly effective in a gun of small, portable size that may be held and operated by one hand.

The guns of the prior art have not proved entirely satisfactory, especially in use for running continuous beads of stiffer liquid materials, such as plastic and rubber base sealants that, for one example, are used between the windshield glass and rubber mountings in automobiles, boats, and aircraft. Continuous cycling of the handle is needed, but with the prior art guns there is a tendency for the material not to flow fast enough to fill the barrel each time the handle is cycled, thus allowing voids of sealant.

The present invention has as its first objective an arrangement that will provide a positive force to cause the material to flow from the reservoir or source into the gun barrel. includes a supplemental piston that forces air into the reservoir so that it can act against the liquid therein and aid in causing that liquid to flow into the gun barrel.

It is a particular feature of the present invention that the air pump for forcing air into the reservoir is operated by the same means and at the same cycle as is the pump means for delivering the liquid to the nozzle.

A further object of the invention is to provide for delivering a larger volume of air into the reservoir than the volume of liquid delivered by the liquid pump. This enables the apparatus to be pumped up rapidly so as to produce a positive pressure acting against the liquid after a relatively few cycles of the pump handle or other operating means therefor. It also aids in dispensing more viscous materials.

Anther object of the invention is to provide an apparatus of this kind in which the liquid may be contained in an inner flexible walled reservoir, such as a collapsible dispensing tube removably attached to the gun mechanism, whereas the compressed air is confined in an outer container surrounding the tube so as to act upon the :fiexible wall thereof to squeeze or compress the tube and force ejection of its contents into the pump cylinder.

In the preferred embodiment, this arrangement I This affords a gun that can be refilled by simply attaching a new tube of material onto the gun, which is of great value.

Other objects include an arrangement in which the pumping handle and other parts of the gun may be squeezed together to produce the pumping action aforesaid; and to provide an apparatus in which the liquid pumping apparatus and the air supply pump elements are operated by the same cycle of the single operating handle.

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In the drawings:

Figure l is a plan view of the pumping apparatus;

Figure 2 is an elevation of the upper part thereof viewed from the left side of Figure 1;

Figure 3 is an elevation of the upper part thereof viewed from the right side of Figure 1 with the trigger slightly modified;

Figure 4 is a substantially medial section through the gun deviated to cut through the liquid pumping cylinder;

Figure 5 is a view similar to Figure 4, the section being taken through the air pumping cylinder;

Figure 6 is a horizontal section taken through the reservoir looking toward the bottom of the gun casing, as shown on the line 6-6 of Figure 2; and

Figure 7 is a transverse section broken away at the top, showing how the arrangement may be used with a collapsible tube that contains the liquid contents to be discharged.

The gun comprises an upper gun attachment and head 10 and a reservoir container 11. The reservoir in the showing of Figure 4 consists of a can of liquid or semiliquid material. In Figure 7, the reservoir is shown constituting a flexible or collapsible tube 12 surrounded by a can or similar hollow container 13 for a purpose later to appear.

Referring first to the portions illustrated in Figures 1 through 6, the pumping structure includes a casing or head 15 that may be a die-casting or the like. It has a lower internally threaded flange 16 thatis engageable over a corresponding externally threaded flange 17 of the container 11. An appropriate gasket of leather or the like, is used to insure a seal between the casing 15 and the container 11, secure against elevated pressure within the container.

A dual pumping arrangement'is provided in the casing 15. It includes an air pumping device generally indicated at A, shown particularly in Figure 5, and a liquid pumping device generally indicated at L, shown particularly in Figure 4. The air pumping device A has a cylinder 20 extending transversely of the upper part of the casing 15. The cylinder is plugged by a threaded plug 21 at one end and at its other end it has a smaller passage 22 coaxial with the cylinder 20, through which a piston rod 23 may slide. An appropriate form of packing gland, such as a Teflon O-ring 24 and a threaded plug 25, are designed to seal the piston rod 23 in the casing.

The piston rod 23 is attached to a composite piston 26. The piston 26 includes two opposed discs that compress a gasket arrangement 261 between them. It is, of course, understood that some synthetic material, such as Teflon may be used for the gaskets, or that other piston sealing devices can be used as necessary or convenient. The composite piston 26 is mounted upon a threaded extension 27 of the piston rod 23. Nuts 28 Other objects will appear from the description to folthe piston 26 to move thepiston on a suction stroke,

which isto the right in Figure}. .An external spring. 321 is also shown around the piston 23 outside thecyl- To provide for air ingress to the cylinder 29; there s 33 p je pw ly rom, he. casin 1 His drilled through to thecylinder 20, and receivesa small, externally threaded fitting 34th at has an air port 35 and that provides a valve seat 36. Aball valve 37 isspring-pressed upwardly by acoil spring 38 so thatn rmally the ball 37 is maintained against the seat 36, but,

can move downwardly therefrom to permit ingressof air through the port 35, around the ball, and thence bythe smaller bore 39 into the cylinder 20. V

The casing also has alower boss 40 within its hollow underpart. This boss is drilled through to the cylinder 20, and threaded to receive a fitting.41 having a port 42. Within the boss 40 there is a ball valve 44 springpressed upwardly by a spring 45 against a valve seat 46. This communicates by a passage 47 into the cylinder 20.

The cylinder 20, to the right of the piston 26, has a bleeder port 49 to prevent trapping ofair back of the piston that might hinder its operation.

It can be seen that the parts of the air pump may be readily assembled and disassembled. If the plug 21 is removed from the head of the cylinder 20, the spring and piston parts may be removedthrough the leftend of the cylinder, and repaired,.replaced, or adjusted. The opposite plug 25 can be removed or resettoattend to requirements of the packing 24. The fitting 34 may be removed to permit attention to the inlet check valve parts, and the fitting 41, may be removed through the bottom of the casing to give access to the oulet air check valve parts.

T heliquid pumping arrangement is shown more par ticularly in Figure 4. It includes a cylinder 60 transversely disposed in the casing 15, parallel 'to thecylinder 2.0. A threaded plug 61 closes the endof the cylinder 60. Within the cylinder, there is a piston 62 that may be built up of parts similar to those of the air piston 26. This dispensing piston 62 is on a piston rod 63 that projects through the closed end of the cylinder 60. Packing is not ordinarily necessary around the piston rod 63.

A coil spring 64 is provided within the cylinder 60 acting between the plug 61 and the piston 62to urge the piston to the right in Figure 4, which is on its suction stroke. Supplementally or alternatively to the spring 64, a spring 65 may be mounted around the ex ternal part of the piston rod 63, to urge the piston to the right. Where viscous, sticky materials are dispensed, the .internal spring should be avoided.

The action of the piston 62 is to draw liquid from the container 11 and to discharge it through the gun nozzle. The hollow bottom portion ofthe casing has a boss which is bored through to the cylinder 60, and'threaded at its lower end to receive a fitting in the form of a spud or nipple 67. The upper end of this fitting has a valve seat 68 upon which a ball valve 69 normally rests. Above the ball valve 69, the passage 70 communicates into the cylinder 60. A spring 71 urges the valve 69 against its seat. 7

The lower end of the spud 67 has a tube 72 attached to it by a union 73. The tube 72 extends to the lower part of the container 11 so as to provide for expulsion of all the liquid therein. The tube 72 and passages should be large enough to pass viscous materials such as heavy rubber cements, plastic sealants, etc., suggested above. Aninternal diameterofiMl inch is usually'appropriate for the tube 72. e

The delivery from the cylinder 60 'is by a nozzle.- A bore 75 at the to'pof the casing 15 is drilled'through to the cylinder 60, providing a passage 76 aligned with the lower passage 70 for easy cleaning, the passage 76 leading from the cylinder into a valve seat 77 and thence into an enlarged chamber 78. This chamber contains a ball valve 80 cooperable with the valve seat 77, and urged onto the seat by a spring 801. The chamber is closed by a removable plug 81. A nozzle 82 extends laterally from the boss to overlie the piston rods 23 and 63, with its bore,83 connecting into the chamher;78: The chamber is sufficiently large for permitting cleaning of the bore 83. Astrengthening web 84 joins the nozzle 82 with the cylinders. The nozzle can have an elongated, removableand replaceable extension 85, with the end shaped so that it can be brought into the corner of Windshields to eliminate the danger of glass breakage. Also, it is useful for laying even beads of sealant to seams, etc.

The base. 82 of the nozzle is preferably part of the casting forming the casing of the gun. It hasan ear forming a pivot base for a trigger handle 91. The

trigger handle 91 is wide enough to engage both piston rods 23 and 63, and should be hardened to resist wear in use.

In Flglll'fij, the tube 12 has its usual threaded top opening 95 received in an adaptor 96 that engages the nipple 67. The tube is enclosed in the can l3that may be the same as the can 11. By this arrangement, the material tobe dispensed may be used from the tube until thetube is empty, and then a new tube substituted.- Of course, if the material is in the can 11, when one can is empty, another maybe connected to the dispenser.

Usepf the gun The material to be dispensed may be obtained in cans. When anew supply is to be used, the cap is removed from the can 11 and the casing or-head 10 is screwed onto the can. The dip tube 72 reaches the bottom of the liquid or semi-liquid material. The operator grasps the assembly in one hand, usually with the thumb and palm around the casing 10 and the fingers around the trigger handle 91. The curved and tapered nozzle 85 is positioned to discharge into the creviceor seam to be sealed. The operator squeezes the handle -91 toward the casing 10, driving the piston rods 23 and-63 inwardly (leftward in Figures 4 and 5) to force the air piston 26 and the liquid piston 62 inwardly against the springs 32, 321, 64, and 65. At the start, this does not dispense material from the container 11, but the-piston 26 drives air from the cylinder20 past thevalve 46into the can 11, while the piston 62 expels air from the cylinder 60 past the valve 80. The air from the cylinder20 starts a build-up of air pressure in the can 11, acting against the liquid therein to force it out through the tube 72. The diameter of the piston 26 should be in the nature of twice that of the piston 62.

Then the user releases the trigger 91, whereupon the springs 32, or 321, 64 or 65, force the pistons 26 and 62 outwardly (to the right in Figures 4 and 5) until they reach the end of their outward strokes. This suction stroke of the piston 26 draws new air into the cylinder 20 past the inlet air check valve 37. Simultaneously, the suction stroke of the piston 62 draws liquid via the tube 72, from the can 11 past the inlet liquid valve 69.

After a few cycles of the trigger, liquid is forced into the cylinder 60 on each suction stroke by the suction of the liquid piston 62 and the air pressure produced in the can 11 by the piston 26. Then each subsequent pres sure stroke of the trigger 91 simultaneously forcefully ejects the liquid from cylinder 60 and compresses more air into the can 11.

The air piston displacement exceeds that of the liquid piston. Especially where the gun is used intermittently, it isdesirable to build up the air pressure-rapidly, to speeddelivery of material from the gun. The larger air piston reduces theamount of cycling required to. charge the gun. The stroke of the piston 26 can be adjusted to vary the amount of air delivered to the container 11 by each pressure stroke. This adjustment is accomplished by moving the piston rod 23 in or out relative to the suited to the material being dispensed. Under some conditions requiring extra pressure, the air piston 26 may be individually pumped back and forth without operating the liquid piston 62, thereby building up pressure in the can, by holding back the piston 62 or by splitting the trigger as noted in Figure 3, into two parts 91A and 91B. Then with each subsequent dispensing action, the pressure is maintained by the normal operation of the air piston simultaneously with the operation of the liquid piston. Too much pressure can be relieved by unscrewing can 11 from casing '10.

The present positive pressure gun provides a positive pressure to expel liquid from the can, without dependence upon gravity or the suction differential of the suction stroke of the liquid piston, or the position of the gun (upside down, etc.). It enables the pumping mechanism and all the moving parts to be kept out of the liquid 1 reservoir.

The arrangement of Figure 7 is of particular importance, and represents a method of dispensing liquid or semi-liquid materials not practical without a positive force apparatus. It is obviously desirable to distribute sticky liquids in tubes for certain usages. Among the advantages are convenience of handling cleanliness, and minimum exposure to air during the time the material in the tube is being, from time to time, put to use.

When a tube 12 of material is to be used, its ordinary cap is removed and it is threaded onto the nipple 67 as illustrated. Then the can 13 is threaded around it, so that it is seated onto the casing 10. Then cycling of the handle 91 simultaneously develops low pressure to draw material from the tube, but, in this case, more importantly, it pumps air into the can 13, outside the collapsible tube 12, to squeeze the same and expel its material into the cylinder 60 to be dispensed.

Cleaning of this dispenser is easy. The air pressure parts do not become fouled as readily as do the liquid conducting parts. However, the air passages can easily be cleaned by brushes, and if necessary, by removing the plugs 21, 34 and 41. The liquid parts can be cleaned with solvent, or by use of a tube of solvent in place of the tube 12 in Figure 7, or of the dip tube 72 in Figure 4. The valves are quickly accessible by long brushes. Alignment of the passages 70 and 76 enhances this cleaning. The enlarged chamber 78 makes the nozzle passage 83 readily accessible to a long brush.

It will be understood that many variations may be made within the scope of this invention.

What is claimed is:

1. A method of delivering flowable material from a fluid reservoir means, including a cycle of drawing material from the reservoir means, preventing its return to the reservoir means while expelling it from the seservoir means, and in the same cycle forcing air into confined contact with the reservoir means to build up pressure on the fluid therein to expel material therefrom.

2. The method of expelling flowable material from a collapsible tube, comprising enclosing the tube in a sealed receptacle, developing air pressure in the receptacle outside the tube, compressing the tube walls to eject the contents therefrom simultaneously drawing a suction on the outlet of the tube to draw the contents into a chamber, and finally positively displacing them from the chamber.

3. A dispensing gun, comprising a gun casing, a con-; tainer for material to be dispensed connected to said casing, first valved displacement means operable through a suction and a pressure stroke to draw material from the container and discharge it for use, second valved displacement means operable through a suction and a pressure stroke to draw air in and to force it into confined contact with said reservoir means to increase the pressure upon said fluid, and actuating means including an operating element movable to cause movement of both displacement means at once.

4. The dispensing gun of claim 3 in which a collapsible tube is disposed Within the container, said tube having an outlet communicating with said first valved displacement means.

S. A dispensing gun comprising a container for material to be dispensed, a casing attached thereto, first valved displacement means operable through a suction and a pressure stroke to draw material from the container and discharge it for use, second valved displacement means operable through a suction and a pressure stroke to draw air in and to force it into the container, said displacement means comprising pistons operating in cylinders formed in the casing, said cylinders being arranged parallelly, transversely of the casing, the cylinders being closed by removable plugs to give access to the interiors of the cylinders, each with inlet and outlet passages connecting with the outside air and the interior of the container; the passages being from top to bottom of the casing, each with a ball and spring valve, and each being closed by a removable plug at its end, and actuating means including an operating element movable to cause movement of both displacement means at once, and spring means to move the displacement means in one direction.

6. A dispensing gun comprising a container for material to be dispensed, a casing adapted to be attached to the top of the container, first valved displacement means operable through a suction and a pressure stroke to draw material from the container and discharge it for use, second valved displacement means operable through a suction and a pressure stroke to draw air in and to force it into the container, the two displacement means including parallel devices to operate them, the parallel devices being transverse to the casing, and actuating means including an operating element movable to cause movement of both displacement means at once, said operating element being a trigger generally lengthwise of the gun, and engageable with both parallel devices.

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