US3272393A

US3272393A - Apparatus and method for precision metering and deposit of viscous materials

Info

Publication number: US3272393A
Application number: US330484A
Authority: US
Inventors: John O Roeser
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-12-13
Filing date: 1963-12-13
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

Sept. 13, 1966 Q RQESER 3,272,393

APPARATUS AND METHOD FOR PRECISION METERING AND DEPOSIT OF VISCOUS MATERIALS Filed D60. 13, 1963 fave-722 01 IEXz @fiawer United States Patent APPARATUS AND PLTET HQD FUR lliiEClSlON METERING AND DEPGSET UR VlSCQUS MATE- RIALS John E). Rocser, 8611 Lincoln Ave, Morton Grove, iill.

Filed Dec. 13, 1963, Set. No. 330,484 9 Claims. (Cl. 222-179) This invention relates to an injector for precision metering and deposit of variable quantities of a viscous material such as epoxy resin systems, potting compounds, adhesives and similar materials.

The new epoxy resins are widely used for potting small electronic components and for sealing terminal connections of switches, microphones and similar electronic components. The epoxy resins fall into two broad categories, heat activated one part systems or two part systems that start hardening when mixed.

The two part system finds more general use as it avoids the application of heat to the component being processed and because it is more convenient to handle. One particular problem in the application of the two part system arises from the fact that once mixed, the system progressively becomes highly viscous and tacky and ultimately hardens. Working life may be from a few minutes to one hour. When the material hardens it sticks tenaciously to the mixing and applicator equipment and cleanup is a major problem.

There are presently available, commercial devices utilizing hand held guns having discharge nozzles equipped with finger manipulable valves. These devices have many parts associated with the valving action which must be cleaned. Moreover, the valving motion encumbers precision maneuver of the gun and disturbs the placement of the material. In addition, the discharge passage is relatively long to accommodate the valving mechanism and this results in a shortened pot life for the charge.

For these reasons, there are many in this art who still use toothpicks or hypodermic syringes for applying small amounts of epoxy. Thus, there exists a genuine need for an injector for handling the deposit of viscous materials such as epoxy resin systems.

The principal object of the invention is the provision of an injector for precision metering and deposit of viscous materials.

Another object is the provision of such an injector having facilities controllable to vary the quantity of material to be discharged.

A more specific object of the invention is the provision of a method and an apparatus employing a hand maneuverable storage and discharge cartridge equipped with a flexible air pressure supply controlled by a proportional treadle movement to provide a full range of variable control without disturbing the cartridge placement.

A further object of the invention includes the provision of injector apparatus characterized by a reuseable cartridge having a cylindrical reservoir and provided with a full size air inlet opening at one end and a short valveless discharge nozzle at the other end.

Still another object is the provision of an injector apparatus characterized by a cartridge having a reservoir for receviing a charge of viscous material, a short valveless discharge nozzle at one end and a flexible air supply line at the other end to apply air under pressure directly against the charge.

Other and further objects of the present invention will be apparent from the following description and claims, and are illustrated in the accompanying drawings which show structure embodying preferred features of the present invention and the principles thereof, and what is now 3,272,393 Patented Sept. 13, i966 considered to be the best mode in which to apply these principles.

In the accompanying drawings:

FIG. 1 is a diagrammatic side view partly in section illustrating a preferred injector apparatus constructed in accordance with this invention;

FIG. 2 is a sectional view through a cartridge and showing a self-contained charge therein;

FIG. 3 is a sectional view through a cartridge that is equipped with a floating piston; and

FIG. 4 is a sectional view through a dispenser cartridge in the form of a can equipped with an air inlet line and liquid discharge line.

Referring now to the drawings, and particularly to FIG. 1, a complete injector assembly is illustrated for the precision metering and deposit of variable quantities of viscous material such as epoxy resin systems, potting compounds and adhesives. The assembly includes a pressure regulating valve unit 10 of basically conventional form which is here shown mounted on a bench top T. The valve 10 has a valve casing 11 provided with an air inlet passage HI, an air outlet chamber 11C and an air vent chamber 11V. Air flow from the inlet passage 111 to the outlet chamber 11C is regulated by a valve head 12 that is biased to closed position by a spring 13 and that includes a stem 12S projecting into the upper end of the vent chamber 11V. A flexible diaphragm 14 divides the vent chamber and includes a central disc 12D provided with a port 121 which is normally closed by the valve stem 128.

The valve unit It has its lower end projecting through the bench top T and equipped with a vertically slidable plunger 15 which transmits force to the diaphragm 14D by means of a load spring 16 housed within the vent chamber 11V. The plunger 15 constitutes an externally accessible actuator that is shiftable for applying a proportional force to the diaphragm to elevate the valve head 12 and open a flow passage through the valve from inlet 111 to outlet 111. As is conventional, the resultant pressure acting at the outlet HP is variable in accordance with the position of the valve head 12.

Finally, the valve has an internal vent passage 17 establishing communication between the outlet chamber 11C and the upper region of the vent chamber 11V. In the event the valve has been set to some selected valve opening position and air under cor-responding pressure is being supplied to and through the outlet chamber, an abrupt closure of the valve head 12 by release of the plunger 15 results in an excess air pressure on the downstream side of the valve. An important feature of this valve is that this excess of pressure is dumped rapidly to facilitate instant shut-off. The dumped air follows a path that extends from the outlet chamber through the internal vent passage 17, through the port lZP in the diaphragm disc 12D which is now open by virtue of the existence of the excess downstream air pressure, and finally through an external vent passage 18 that leads from the vent chamber 110.

In the injector arrangement constructed in accordance with this invention, the valve unit 10 has its air inlet passage 11I equipped with a feed line 19 connected to a source of air under pressure, its air outlet passage 11C connected to an air supply line 20, and its pressure regulating proportional plunger 15 connected to be controlled by a treadle actuated mechanism for regulating the supply of air to the desired pressure.

As illustrated herein, the treadle actuated mechanism includes a lever 21 pivotally mounted to the bench. One end of the lever 21 underlies the plunger 15' and the other end is connected to a cable 22 which extends upwardly from a treadle 23 that may be pivotally mounted on a suitable floor mounted base 24 to enable the operator to 1?) apply proportional control by foot action on the treadle and position the plunger to select any desired air pressure. By this arrangement, air turn-on and air shutofi. and all graduations in the pressure selection are effected by treadle control of the valve unit It and the operators hands are free to handle the injector head or cartridge 25.

In the preferred form of the invention the injector head 25 is in the form of a re-usable cartridge defining a reservoir R for receiving a charge C of viscous material and having an endwise directed orifice discharge passage P at one end and a cup shaped cap as removably mounted in air tight sealed relation around the other end. The air supply line 2t is in the form of an elongated flexible air supply tube having one end connected to the air outlet chamber 11C of the valve unit and having the other end connected in sealed relation to the cartridge cap 25 to communicate with reservoir R through a passage MP in the cap.

The cartridge is of a size to facilitate grasping and maneuver by one hand and typical cartridges may be of the following sizes: a /2 inch diameter cartridge may have a reservoir volume of /3 cubic inch and an orifice diameter of .032 inch. A 1% inch diameter cartridge may have a reservoir volume of five cubic inches and an orifice diameter of .062 inch.

In one preferred embodiment of the invention as illustrated in FIG. 1, the cartridge 25 is of one-piece construction and includes a housing portion 25H providing a cylindrical reservoir R having a full sized inlet opening across the air entry end thereof, and a valveless nozzle portion ZSN rigidly carried on the housing portion 25H at its opposite end and providing an endwise directed orifice discharge passage for the reservoir. The cartridge reservoir is filled through its large open end with a charge C of viscous material such as a two part epoxy resin sys-- tem and the cartridge is then hand-guided to locate its nozzle exit at a position for depositing a controllable quantity of the viscous material. For this purpose the operators foot applies proportional control through the treadle 23 and the motion transmitting cable 22 and lever 21 to open the valve unit appropriately for applying air at the required pressure directly to the charge of viscous material which is then extruded from the cartridge at an appropriate rate.

As soon as the operators foot returns the treadle 23 to initial position and an external return spring 27 restores lever 21 to enable the plunger to be returned to the air-off position, an excess of pressure exists downstream of the valve 10. This excess downstream pressure deflects the diaphragm J14 downwardly to open the vent port 12F and permit dumping of the downstream air. This action facilitates instant shut-oil and eliminates drippage from the nozzle. During the actual depositing action the flow of the viscous material may easily be varied in accordance with the requirements of the particular operation, all of this being accomplished by proportional treadle movement and thus in no way interfering with the precision location and hand guidance of the cartridge head.

There is particular advantage in the fact that the air under pressure is applied directly to the charge C of viscous material. This gives fast response and reduces the effort required in the case of highly viscous resins. More importantly, however, the shut-off response is much quicker than would be the case where the pressure is applied through a piston 28 mounted in floating relation in the reservoir as illustrated in FIG. 3. In the latter instance, friction is always acting between the piston and the cartridge walls so that when air pressure behind the piston is reduced, friction causes the piston 28 to remain at its advanced position wherein it pushes against the charge of material. In addition, it is inevitable that air bubbles will exist forwardly of the piston 28 and being under a high degree of compression, they will produce forces that con tinue to push out resin, even after air shut-off. The technique of using air under pressure to contact directly against the charge is useful for injection of any type material that will slump sufiiciently to prevent air from tunneling through to the nozzle.

Other features in the cartridge arrangement reside in the fact that the nozzle ZSN is valveless, permitting the orifice passage to be of minimum length. Moreover, the reservoir R is immediately adjacent the nozzle so that the material has a short overall travel path when exiting from the cartridge, thus facilitating extrusion of highly viscous materials.

Another important practical aspect of the invention is that the viscous material touches only a single part--the cartridge 25 and it has a configuration that facilitates cleanup. Thus, the cylindrical reservoir R having a full width opening at the air inlet end, enables a drill to be inserted for cleanout of the reservoir after the resin has hardened therein. Another drill may be inserted through the nozzle end to complete the cleaning operation and enable re-use of the cartridge. Thus, the invention permits the use of expensive precision nozzles as cleanup is no longer a problem. It should be noted that the invention also contemplates that disposable cartridges 25 might be employed instead of the re-usable cartridges described previously.

Another variation of the device is illustrated in FIG. 2 wherein the cartridge 25 is shown equipped with a charge C which includes a plastic carrier bag 29 having a nozzle 29N press fit into the cartridge. The bag is useful in facilitating initial insertion of the charge into the reservoir and it is collapsible progressively with expulsion of the charge from the reservoir. This FIG. 2 arrangement has the advantage of preventing the resin from contacting the housing portion 25H of the cartridge.

While the floating piston arrangement as indicated previously has certain disadvantages, the invention does contemplate the use of such a floating piston 28 for certain applications and such an arrangement is shown in FIG. 3.

Finally, another cartridge arrangement is illustrated in FIG. 4 wherein a closed one quart 29 can serves as the cartridge and is equipped with a flexible air supply line 26 shown entering at the top and a liquid delivery tube 3%) shown extending from a location adjacent the bottom of the can through the top to act as the injector nozzle. This can-type cartridge is normally contemplated for use with a one part resin.

While proportional air pressure control is contemplated for precision depositing operations, it should be apparent that the injector in many instances may be used with a direct three-way air valve to provide a simple on-ofi arrangement for controlling the supply of air to the cartridge. Even in simple on-off arrangements of this type, there is important advantage in the fact that the cartridge is freely hand maneuverable and the on-off control is effected by the treadle 23 and thus in no way disturbs the guidance of the cartridge.

Thus, while preferred constructional features of the invention are embodied in the structure illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit and scope of the appending claims.

What is claimed is:

1. In an injector for one-handed precision metering and deposit of variable quantities of viscous material, the combination with an air pressure valve unit having an air inlet connected to a source of air under pressure, an outlet, and means for controlling flow of air under pressure from said air inlet to said air outlet; of a cartridge of a size and shape suitable for engagement and maneuver by hand and including a housing portion providing a reservoir for receiving a charge of viscous material and a valveless nozzle portion rigidly carried on said housing portion and providing an orifice discharge passage! f0! said reservoir, means including an elongated flexible air supply tube having one end connected to said air outlet and having the other end connected in sealed relation to said housing portion for supplying air under pressure into a region of said reservoir remote from said nozzle portion to eflect application of pressure on said charge, and treadle actuated mechanism connected to said controlling means for controlling the supply of air under pressure to said tube.

2. In an injector for one-handed precision metering and deposit of variable quantities of viscous material, the combination with an air pressure valve unit having an air inlet connected to a source of air under pressure, an outlet, means for controlling flow of air under pressure from said air inlet to said air outlet and means for dumping downstream air when downstream air pressure is in excess of that corresponding to the value determined by said controlling means; of a cartridge of a size and shape suitable for engagement and maneuver by hand and including a housing portion providing a reservoir for receiving a charge of viscous material and a valveless nozzle portion rigidly carried on said housing portion and providing an orifice discharge passage for said reservoir, means including an elongated flexible air supply tube having one end connected to said air outlet and having the other end connected in sealed relation to said housing portion for supplying air under pressure into a region of said reservoir remote from said nozzle portion to eifect application of pressure on said charge, and treadle actuated mechanism connected to said controlling means for controlling the supply of air under pressure to said tube.

3. An injector for one-handed precision metering and deposit of variable quantities of viscous material and comprising a cartridge of a size and shape suitable for engagement and maneuver by hand and including a hous ing portion providing a reservoir for receiving a charge of viscous material and a valveless nozzle portion rigidly carried on said housing portion and providing an orifice discharge passage for said reservoir, means including an elongated flexible air supply tube connected in sealed relation to said housing portion for supplying air under pressure into a region of said reservoir remote from said nozzle portion to contact directly against said charge, and a treadle actuated mechanism for controlling the supply of air under pressure to said tube.

4. In an injector for one-handed precision metering and deposit of variable quantities of viscous material, the combination with an air pressure valve unit having an air inlet connected to a source of air under pressure, an outlet, and means for controlling flow of air under pressure from said air inlet to said air outlet; of a hand maneuverable dispensing unit including means forming a reservoir for receiving a charge of viscous material, and a valveless nozzle tube providing an orifice discharge passage having one end in direct communication in the charge contained in said reservoir and having a discharge end projecting from said reservoir, means including an elongated flexible air supply tube having one end connected to said air outlet and having the other end connected in air tight sealed relation to communicate directly with said reservoir at a region thereof to effect application of pressure on said charge for forcing said liquid out said nozzle tube, and treadle actuated mechanism connected to said controlling unit for controlling the supply of air under pressure to said tube.

5. An injector for one-handled precision metering and deposit of variable quantities of viscous material and comprising a reversible cartridge of a size and shape suitable for engagement and maneuver by hand and including a housing portion providing a cylindrical reservoir for receiving a charge of viscous material and having a full size inlet opening across one of said reservoir and a valveless nozzle portion rigidly carried on said housing portion at the other end of said reservoir and providing an endwise directed cylindrical orifice discharge passage for said reservoir, a cup shaped cap removably mounted in air tight sealed relation around one end of said housing portion to span said inlet opening and having a central through passage, an elongated flexible air supply tube having one end connected to said cap to supply air through said passage to contact directly with the material in said reservoir, an air pressure regulator connected to the other end of said tube for supplying air under pressure to said reservoir and including means for dumping air when downstream air pressure is in excess of that corresponding to the regulator setting, and a proportional treadle actuated mechanism for varying the pressure setting of said regulator.

6. An injector for one-handed precision metering and deposit of variable quantities of viscous material and comprising a reusable cartridge of a size and shape suitable for engagement and maneuver by hand and including a housing portion providing a cylindrical reservoir for receiving a charge of viscous material and having a full size inlet opening across one end of said reservoir and a valveless nozzle portion rigidly carried on said housing portion at the other end of said reservoir and providing an endwise directed cylindrical orifice discharge passage for said reservoir, a cup-shaped cap removably mounted in air tight sealed relation around one end of said housing portion to span said inlet opening and having a central through passage, an elongated flexible air supply tube having one end connected to said cap to supply air through said passage to contact directly with the material in said reservoir, an air pressure regulator having an air inlet connected to a source of air under pressure, an air outlet connected to the other end of said tube, valve means for regulating flow of air from said air inlet to said air outlet, an externally engageable actuator shiftable for applying a proportional force to open said valve means, and means for dumping downstream air when downstream air pressure is in excess of that corresponding to the current position of said actuator, a treadle mounted for reversible movement, and motion transmitting mechanism connected between said treadle and said actuator for effecting variation in air pressure applied to said reservoir in proportion to movement of said treadle.

7. An arrangement in accordance with claim 1 and wherein said cartridge has a floating piston in said reservoir and having one face exposed to air under pressure supplied through said tube and an opposite face exposed to engage against the charge in said reservoir.

8. An arrangement in accordance with claim 1 and wherein said charge includes a collapsible bag that receives the liquid and that has said nozzle portion integral with said bag and projecting in press fit relation through said housing portion.

9. An arrangement in accordance with claim 4 wherein said reservoir forming means comprises a closed can, and said nozzle tube has one end within the can at a lower region thereof and has an opposite end extending outwardly of the can to deliver the charge.

References Cited by the Examiner UNITED STATES PATENTS 160,936 3/1875 Meyer 222--179 166,567 8/1875 Steele 137505.11 1,390,011 9/1921 Bliven 222389 1,465,620 8/1923 Anderson 222-94 X 1,520,745 12/1924 Bowden 222394 X 1,888,310 11/1932 Davis 2S1295 X 2,615,598 10/1952 Watkins et a1. 222-397 2,665,825 1/ 1954 Poitras et al. 222-179 X 2,709,542 5/1955 Eller et a1. 222-394 X 3,124,276 3/ 1964 Grout 222394 X ROBERT B. REEVES, Primary Examiner.

LOUIS J. DEMBO, EVON C. BLUNK, Examiners.

F. R. HANDREN, H. S. LANE, Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,272,393 September 13, 1966 John O. Roeser It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 65, for "one-handled" read one-handed line 71, after "one" insert end Signed and sealed this 29th day of August 1967.

(SEAL) Attest:

ERNEST W. SWIDEB Attesting Officer EDWARD J. BRENNER Commissioner of Patents

Claims

1. IN AN INJECTOR FOR ONE-HAND PRECISION METERING AND DEPOSIT OF VARIABLE QUANTITIES OF VISCOUS MATERIAL, THE COMBINATION WITH AN AIR PRESSURE VALVE UNIT HAVING AN AIR INLET CONNECTED TO A SOURCE OF AIR UNDER PRESSURE, AN OUTLET, AND MEANS FOR CONTROLLING FLOW OF AIR UNDER PRESSURE FROM SAID AIR INLET TO SAID AIR OUTLET; OF A CARTRIDGE OF A SIZE AND SHAPE SUITABLE FOR ENGAGEMENT AND MANEUVER BY HAND AND INCLUDING A HOUSING PORTION PROVIDING A RESERVOIR FOR RECEIVING A CHARGE OF VISCOUS MATERIAL AND A VALVELESS NOZZLE PORTION RIGIDLY CARRIED ON SAID HOUSING PORTION AND PROVIDING AN ORIFICE DISCHARGE PASSAGE FOR SAID RESERVOIR, MEANS INCLUDING AN ELONGATED FLEXIBLE AIR SUPPLY TUBE HAVING ONE END CONNECTED IN SEALED AIR OUTLET AND HAVING THE OTHER END CONNECTED IN SEALED RELATION TO SAID HOUSING PORTION FOR SUPPLYING AIR UNDER PRESSURE INTO A REGION OF SAID RESERVOIR REMOTE FROM SAID NOZZLE PORTION TO EFFECT APPLICATION OF PRESSURE ON SAID CHARGE, AND TREADLE ACTUATED MECHANISM CONNECTED TO SAID CONTROLLING MEANS FOR CONTROLLING THE SUPPLY OF AIR UNDER PRESSURE TO SAID TUBE.