GB2035147A - Fluid dispensing - Google Patents

Abstract

A fluid dispensing apparatus e.g. a hand-held writing instrument comprises a pressurized reservoir 10 for paint or other fluid, which is dispensed through a pointed hollow head 24 communicating with the reservoir by a channel 22. The hollow head includes an internal valve seat 30, against which the shoulder 32 of a needle plunger 28 operates. The base 34, 36 of the plunger forms a biased-toward- closed valve actuator and the needle part of the plunger extends through a tip 26 of the hollow head and just beyond the writing point to permit tip writing pressure to back bias the plunger and to thereby permit the flow of fluid from within. One application for the instrument is in connection with filling engraved indentions with paint. <IMAGE>

Description

SPECIFICATION Fluid dispensing This invention relates to fluid dispensing apparatus and particularly to apparatus suitable for dispensing small, but controlled amounts of fluid.

According to the invention, there is provided fluid dispensing apparatus, comprising: a dispensing compartment for storing a volume of fluid and delivering a discrete portion thereof; a valve for receiving, from an external source, gas pressure therethrough into said compartment; a hollow dispensing head having a valve seat opening into said compartment; and a needle valve plunger operating within said dispensing head, the needle part thereof externally projecting beyond said dispensing head, said needle plunger presenting a shoulder biased against said valve seat, the gas pressure causing dispensing of fluid through said dispensing head when said needle plunger is moved by external pressure in opposition to the bias so as to displace said shoulder from said seat.

Preferably, said dispensing compartment comprises a reservoir for storing a volume of the fluid to be dispensed and a dispensing chamber connected by a channel to said reservoir, said receiving valve being arranged to admit gas pressure to said reservoir and said valve seat of said dispensing head opening into said dispensing chamber.

The invention further provides a method of engraving, comprising: forming grooves in the surface of the material to be engraved; and filling the grooves with paint flowing from a gas pressure actuated dispenser, said dispenser including a hollow needle valve writing tip for tracing within the grooves, said needle valve being internally connected to a pressurized reservoir of paint, said needle valve including a biased needle plunger, the tip of which projects beyond the hollow needle writing tip, said plunger internally closing the valve to prevent paint flow until tip pressure back-biases said needle plunger.

This invention is useful in connection with engraving in a manner totally different from the procedure commonly employed. For example, in a known procedure a metal plaque is first engraved, etched or otherwise grooved with letters, numbers or a design. Typically, such grooves vary in width from about .010" to .25", these dimensions being examples of and not limitations on possible groove sizes.

Again typically, grooves are about .003" to .020" deep. After the grooves are wiped clean, the engraver uses a small paint brush to paint or fill-in the grooves. Once the paint is partially dried, then the surface is wiped with paint thinner to remove paint that has inadvertently been painted out of the grooves or which was built-up too heavily. In fact, the common practice is to wipe the whole surface lightly to remove paint from the non-engraved surface; however, this procedure partly removes some paint from all of the grooves.

The main disadvantage of filling in the engraved grooves in the known manner described above is that the work is imprecise since the application rate of a brush is relatively uncontrolled. Clean-up is messy and time-consuming. In addition, the wiping of the partially dried paint dulls the lustre of the high gloss paint normally used. Finally, the inadvertent removal of some paint from all of the grooves during the cleaning operation does not permit, by definition, the letters to be built-up to the same level.

The present invention enables the provision of an improved hand-held fluid dispensing apparatus. The most common type of fluid dispensing apparatus in the prior art is a fountain pen. The closest structures to the embodiment described herein is an ink pen marketed under the brand names Kohr-ih-noor and Mars. These pens have a hollow dispensing head tapering to a writing end and a wire leading therethrough. The head of such a pen is internally grooved to prevent ink from too freely flowing by providing a large surface for capillary action build-up. The wire is used to pump or agitate drying ink. That is, if the ink is not flowing enough, then it is common to shake the pen several times to permit the agitation action to occur. The flow of ink is not cut off by the wire but is accomplished by the size of the grooves, the size of the head opening and the natural viscosity of the ink.

As may be seen, the described embodiment of the present invention may be used in the place of a common ink pen. However, it is particularly well-suited for an engraver's tool for dispensing paint, for applying glue in controlled quantities, for dispensing oil, for dispensing silicone, for dispensing controlled fluids in medical applications, and the like.

Therefore, this invention enables the provision of an improved method for filling engraved indentations, employing an instrument which includes a pressurized reservoir of paint dispensed via a needle valve that permits flow when there is a slight amount of back-bias pressure on the needle plunger.

The present invention thus provides the advantage that the paint is dispensed in an improved controlled manner, thus reducing or eliminating subsequent clean-up operations.

One embodiment of the invention described in detail hereinafter comprises a holder in the form of a hand-held writing instrument. The main part of the holder is a fluid reservoir, such as for holding paint. One end is capped with a gas pressure receiving valve to which a small air or other gas compressor is connected. The other end is capped with a hollow needle scribe head, the internal part of which includes a valve seat and combines with a space in the lower cap to form a dispensing chamber connected by a channel to the reservoir. A resilient needle plunger is shaped and biased in the dispensing chamber to close with the valve seat, the needle part thereof projecting through the head just beyond the tip.Externally applied tip pressure on the needle part back biases the needle valve to unseat the plunger, thereby permitting the air or other gas pressure applied to the reservoir to cause the dispensing of fluid through the head.

In order that the invention may be readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 shows a side view of a preferred embodiment of a fluid dispensing apparatus in accordance with the present invention, the apparatus being shown placed conveniently on a stand; and Figure 2 is a front view of the stand shown in Fig. 1 with a plurality of fluid dispensing apparatus, illustrating the convenience of connecting and disconnecting each fluid dispensing apparatus to a common air or other gas pressure source through a quick action connector.

Now referring to the drawings and first to Fig. 1, a single fluid dispensing apparatus embodying the present invention is illustrated in longitudinal cross-section. The dispenser is generally elongate for convenient hand-holding, such as with a pencil or pen, and is preferably made of a hard acrylic or other hard plastics material. internally there is a large reservoir 10 for storing the paint or other fluid to be dispensed from the apparatus. Reservoir 10 is suitably capped at one end by a cap 12, which may be merely glued or otherwise connected to the open end of reservoir 10.

Cap 1 2 is internally threaded to receive a tank valve 14 carrying a tank valve core 16.

This valve is of the type commonly employed in tyres that permit pressuring from an external gas source connected thereto, normally from a compressed air gas source.

A cap 1 8 closes the lower end of reservoir 10 in the same manner that the cap 1 2 closes the top end. Cap 18 includes an internal dispensing chamber 20 connected to the reservoir 10 via a channel 22. The roof or wall of chamber 20 is peaked nearest the reservoir 10 and is externally open. The external opening is internally threaded to receive therein the body of a dispensing head 24, which may be conveniently thought of as a modified hypodermic needle. Hence, the entire dispensing compartment includes the chamber 20 in the cap 1 8 and the companion and contiguous internal reservoir of the body of the dispensing head.

The external opening from the body of the dispensing head, which is in the form of a needle valve, is through an elongate hollow tip 26, which tapers in scribe-like configuration. A needle valve actuator or plunger 28 operates within the hollow dispensing head whose body completes the dispensing chamber 20. The internal surface 30 of the dispensing chamber surrounding the external opening from the body of the dispensing head is gently rounded to form a valve seat for receipt of a mating shoulder 32 on the valve plunger. It should be noted that when the shoulder 32 is in mating contact with the seat 30, the needle part of plunger 28 externally extends or projects slightly beyond the head 26.

The part of the plunger 28 which operates in the internal chamber 20 extends between the shoulder 32 at one end and an abutting end 34 that fits into the peak of the chamber 20. This part of the plunger is resilient biased, such as by a spring 36 connecting shoulder 32 to end 34, so as to press the shoulder 32 against the seat 30.

In operation, the tank valve 14 or the tank valve core 1 6 is removed from the cap 1 2 and the reservoir 10 is filled with the fluid to be dispensed. The valve 14 or the valve core 1 6 is replaced and quick action connector 38 is snapped over the tank valve to apply air or other gas pressure via a flexible tube from a pump 42.

When the dispenser is placed against a surface by the operator, the plunger 28 is moved in opposition to the bias applied by the spring 36 and the shoulder 32 is displaced from the seat 30. Hence, there is a flow path from the dispensing compartment around the shoulder permitting the even flow of fluid through the opening in the head. Flow is shut off by the mere release of pressure on the plunger by the operator lifting the dispensing head.

A regulator 40 ensures that there is an even and sufficient pressure to force the flow of fluid from the dispensing head, taking into account the viscosity of the fluid and the size of the opening in the head. The regulator 40 may determine the resulting pressure supplied to tank valve 14 by varying the voltage supplied to the pump but other means of controlling the pressure may be used. For example, the resulting pressure may be controlled by regulating a pressure bleed.

Referring now to Fig. 2, it may be seen that the apparatus shown in Fig. 1 and described above, may be conveniently stored on a stand 44 having a bar 46. The bar 46 is formed with a plurality of blind holes 48a, 48b, 48c and 48dfor receiving the heads of the individual dispensers the cap 1 8 in each case resting on the bar 46. It may now be observed that the quick action connector 38 connected to the end of a flexible tube leading to the pump 42, permits the air or other gas source to be quickly changed from one dis penser to the next. Conveniently, such a quick action connector includes a lever that actuates the valve stem while sealing off the tank valve. However, a conventional screw-on con nector may be used, if desired.

The pump 42, the output of which is controlled by the regulator 40, may be of any convenient type, although usually a small pump driven from a conventional ac voltage source connection is employed. Such a pump permits variation of the gas pressure with the regulation of the voltage applied. For example, one common controlled variable pump supplies pressure in the range of about 4 psi by varying the stroke of the pump in accordance with the applied voltage. Varying the stroke varies the resultant pressure. Such a pump may sit on the return part of an "L" stand 44, as shown in Fig. 1.

While a particular embodiment of the invention has been shown and described, it will be understood that the invention is not limited thereto, since various modifications may be made. For example, the reservoir 10 and chamber 20 may be open to each other to form one unitary compartment, if desired. In such case, the internal part of needle plunger will be biased against a fixed part of the apparatus other than the peak of the chamber 20. Also, bias can be provided by means other than spring 36, such as by a side holding leaf spring.

Claims (11)

1. Fluid dispensing apparatus, comprising: a dispensing compartment for storing a volume of fluid and delivering a discrete portion thereof; a valve for receiving, from an external source, gas pressure therethrough into said compartment; a hollow dispensing head having a valve seat opening into said compartment; and a needle valve plunger operating within said dispensing head, the needle part thereof externally projecting beyond said dispensing head, said needle plunger presenting a shoulder biased against said valve seat, the gas pressure causing dispensing of fluid through said dispensing head when said needle plunger is moved by external pressure in opposition to the bias so as to displace said shoulder from said seat.

2. Fluid dispensing apparatus according to claim 1, including bias stop means internally positioned within said compartment, and bias means operating between said bias stop means and said shoulder.

3. Fluid dispensing apparatus according to claim 1, wherein said dispensing compartment comprises a reservoir for storing a volume of the fluid to be dispensed and a dispensing chamber connected by a channel to said reservoir, said receiving valve being arranged to admit gas pressure to said reservoir and said valve seat of said dispensing head opening into said dispensing chamber.

4. Fluid dispensing apparatus according to claim 3, wherein the external configuration of said reservoir is conveniently sized for holding in the hand.

5. Fluid dispensing apparatus according to claim 3 or 4, wherein said receiving valve is a tank valve.

6. Fluid dispensing apparatus according to any one of claims 3 to 5, wherein said dispensing head is externally shaped to form a scribing configuration.

7. Fluid dispensing apparatus according to any one of claims 3 to 6, wherein the internal part of said needle plunger bears inwardly against the facing wall of said dispensing compartment, and wherein said needle plunger part between the wall-bearing location and said valve seat includes resilient means.

8. Fluid dispensing apparatus according to claim 7, wherein said resilient means includes a spring.

9. Fluid dispensing apparatus according to any preceding claim and including external gas pressure source means connected to said receiving valve.

1 0. Fluid dispensing apparatus according to claim 9, wherein said gas pressure source means includes a controllable variable pressure motor.

11. Fluid dispensing apparatus according to claim 10, wherein said gas pressure source means includes a quick-disconnect attachment for connecting to said receiving valve.

1 2. A method of engraving, comprising: forming grooves in the surface of the material to be engraved; and filling the grooves with paint flowing from a gas pressure actuated dispenser, said dispenser including a hollow needle valve writing tip for tracing within the grooves, said needle valve being internally connected to a pressurized reservoir of paint, said needle valve including a biased needle plunger, the tip of which projects beyond the hollow needle writing tip, said plunger internally closing the valve to prevent paint flow until tip pressure back-biases said needle plunger.

1 3. Fluid dispensing apparatus substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.

1 4. Any novel feature or combination of features herein described.