WO1988001202A1

WO1988001202A1 - Contact-free drawing pen (''air-brush'')

Info

Publication number: WO1988001202A1
Application number: PCT/NL1987/000019
Authority: WO
Inventors: Gijsbertus Maria Theodorus Gielisse
Original assignee: Grafic World V.O.F.
Priority date: 1986-08-20
Filing date: 1987-08-20
Publication date: 1988-02-25
Also published as: JPH01500648A; EP0277201A1; NL8602123A

Abstract

The contact-free drawing pen consists of a holder (26) for receiving a drawing pen (2) with a writing pen (22, 23). In the holder (26), writing pen (22, 23) is surrounded by a through hole with centre line (15) and with a somewhat larger inner diameter than the outer diameter of the writing pen. Another through hole (20), intersecting through hole (15), is provided with a ball valve (11, 12) and operating pen (10) which is operated by operating element (8) for selectively providing a flow of pressure medium from supply channel (28) through the annular gap between the writing pen (22, 23) and surrounding hole. Thereby a concentric outward medium flow is formed around said writing pen (22, 23), focussing the jet of dye which emerges out of the writing pen (22, 23). Thus a good defined spray can be produced with good delineation of areas and sharply drawn lines.

Description

Contact-free drawing pen ("air-brush")

The invention relates to a contact-free drawing pen ("air-brush") consisting of a holder for receiving a drawing pen with a dye reservoir and a writing pen, communicating with the dye reservoir via a capillary, of the type consisting of a tube and a wire which projects with axial play therein and is capable of limited movement and which may project out of the end of the tube, which holder is provided with a connection to a source of medium under pressure, with a jet nozzle which engages with the writing pen, and with a valve which can be operated manually and which is in communication between the pressure medium connection and the jet nozzle. Such a drawing pen is known from the European

Application 0,092,359 Said known drawing pen consists of a holder in which it is possible to place a drawing pen of the type which is provided with a felt tip and with which through contact with the surface to be written on, lines and the like can be made on said surface. Said holder carries a valve, which can be operated with a finger, in a hole extending parallel to the centre line of the felt pen, which hole is connected, on the one hand, to a pressure medium source and, on the other hand, to a nozzle whose centre line makes an angle with the centre line of the felt tip, which hole is provided downstream of the valve with an adjustable throttling element which has to do service in achieving a fine adjustment of the quantity of air which can spray via the nozzle onto the point of the felt tip. If this is done, the stream of gaseous medium, such as compressed air, emerging from the nozzle ensures that the dye particles a r e removed from the felt tip and dispersed in the form of a spray. In this manner it is

to draw and colour and rule lines without contact occurring with the surface to be processed so that the user is no longer impeded by the fri ction of the pen on the surface.

A disadvantage of said known contact-free drawing pen with felt tip is that, as a result of directing the jet of medium onto the felt tip at an angle, a wide and irregular spray is produced as a result of which it is impossible to work with sharp area boundaries or lines. According to said publication, instead of the felt tip it is also possible to place a pen in the holder of the type in which the writing pen section consists of a tube with a wire or pin therein and capable of projecting somewhat out thereof and which is to some extent moveable with res-pect to the tube. Said known writing pens are very widely used for normal artwork for which it is important to rule lines of a certain width or thickness, which width is determined by the diameter of the tube end. If such a pen known per se is used in the holder drawn and shown for felt tips, it is equally impossible to produce a precise delineation by means of lines and areas on the surface to be processed, such as the paper, as a result of the angled position of the jet of medium with respect to the centre line of the writing pen section.

In addition, the valve operation has the drawback of any valve which is forced into the closed position by the pressure medium and has to be opened against the force of a spring and also of the pressure medium. As soon as opening has taken place, the force of the pressure medium is largely eliminated. The operating finger then experiences a different counter pressure and, with inadequate compensation of the spring pressure, this makes it difficult to control the quantity of air which emerges. This is the reason why said known pen is provided with a throttling element, situated downstream of the valve, with which the passage of the quantity of medium allowed through the valve can be increased or decreased and with which it is intended to bring about a regulation of the outward flow of pressure medium from the jet nozzle of the pen without compensation of the spring pressure. To perform such a regulation the drawing operation has to be interrupted. Said known pen is fairly bulky. The holder section for receiving the pen and the house forming a whole at this point for valve, throttling element and jet nozzle are larger than the p e n itself. The known pen does have the advantage that it is possible to change pen, and consequently colour, at any instant without anything having to be cleaned.

In particular, contact-free drawing pens are also known which a r e based on the principle of the paint spray and which are provided with a nozzle having a regulating needle, to which nozzle pressure medium and dye are concentrically fed and with which both the quantity of pressure medium and also the quantity of dye are therefore regulated. With said pens based on the paint spray principle, a better defined spray can be produced than in the case of angled blowing and good delineation of the areas concerned or sharp lines can therefore be achieved.

In addition, said known drawing pen has the drawback that the construction is relatively expensive and that, if the colour is changed or if it is not used for a long period, the jet nozzle and the needle have to be cleaned. This means dismantling and assembling, and consequently the risk of damage, in particular if fine sizes are involved. The object of the invention is therefore to provide a contact-free drawing pen which h.as the advantages of the pen as it is known from the European Patent Application 0,092,359, but lacks the disadvantages thereof, as well as the disadvantages of pens which a r e based on the paint spray principle, and which is light and v e r y compact in construction and can be manufactured v e r y cheaply. In addition, the object of the invention is to provide a pen which is very easy to handle and can be very satisfactorily controlled.

According to the invention this object is achieved in that the holder has a first through hole having a first part for receiving the housing of a drawing pen in a sealed manner and detachably

a second part of smaller diameter which concentrically surrounds the tube of the writing pen with play, and a third part, situated between said parts, which is in communication with a second hole whose centre line crosses that of the first hole and in which there is, at a distance from the third part of the first hole, an axially moveable valve which is under spring pressure in the pressure medium supply, which engages with an operating pin and which extends transversely through the third part of the first hole and projects outside the holder on the side facing away from the valve and engages at that point with an operating element.

As will be evident below, the holder is extremely small in relation to the dimensions of the pen, which is in any case not large. Because the writing pen section of the pen projects concentrically into the hole which forms the jet nozzle, i.e. into the second part of smaller diameter, the pressure medium flows concentrically around the dye entrained from the pen and the dye remains more or less precisely confined in accordance with the axial postion of the end of the writing pen section with respect to the debouchment of the jet nozzle section. As a result of this, much sharper lines can be ruled, the diameter of the wire determining the thickness of the sprayed line.

If blowing is at an angle, as in the case of the known pen, this cannot be achieved. Because the holder has two holes which cross each other, one of which contains the pen section and the other of which contains the control section, and the control element of the valve crosses the pen section, an extremely compact and consequently also airtight construction is obtained. The valve, which is preferably constructed as a ball valve which engages with an O-ring, can be given such small dimensions that the pressure drop across the valve when it opens no longer plays any part in controlling the quantity to be allowed through so that a very precise control can be achieved with one single valve and operating element. According to the invention, the channel in the holder for supplying the pressure medium to the second hole may extend essentially parallel to the centre line of the f i r s t h o l e .

This achieves the result that the pressure medium supply is not in the way when the pen is being handled.

The invention will now be explained in more detail by reference to the drawings.

Figure 1 shows an embodiment of the invention in side view.

Figure 2 is a front view of the pen in Figure 1. Figure 3 is a section along the line III-III of Figure 1.

Figure 4 is a section along the line IV-IV of Figure 2

Figure 5 is a section through an embodiment which is preferred. The contact-free drawing pen shown in Figure 1 consists of a holder 1, made for example of plastic, into which is inserted a drawing pen, known per se, of which the housing 2 and the cylindrical part 3, which contains the writing pen section and which is inserted in a hole of the holder 1, can be seen.

At 4 there is a tube connection for attaching a flexible tube 5 which can be connected to a reservoir, not shown, containing compressed air which is known per se.

Holder 1 has an operating element 8 which rests on the end 10 of the operating pin of the valve not shown in

Figure 1, which valve is shown in exploded form in Figure 2 and consists of the ball 11, the O-ring 12 and the hold-down spring 13. The connecting nipple 4 is shown hero in the unscrewed condition. Figures 3 and 4 show the same housing on a larger scale and in the specified section.

From said Figures 3 and 4 it can be seen that the holder has a through hole indicated by the centre line 15 for receiving the end 16 of the pen 2, 3. Said hole has a constricted second part 17 and an interposed third part 18, which forms a chamber. The second hole can be seen most clearly in Figure 3 and is indicated by the numeral 19 of its centre line. Said hole has a part 20 of large diameter and a part 21 of smaller diameter. In the part of larger diameter there is the ball valve 11 which engages with the O-ring 12 and which is held in its closed position by the light spring 13. Said spring rests against the nipple 4 The operating pin 10 is guided in the narrower, hole section 21 and projects through the chamber 18 and is in contact with the ball 11. From Figure 3 it clearly follows that if the pin 10 is pressed downwards, the ball will be forced off the O-ring 12 and will permit a communication from the hole section 20 to the chamber 18 so that medium can flow out of said chamber 18 through the narrow hole 17 around the tube 22 of the pen, in which tube the wire or needle 23 is located. The concentric outward flow around said tube and needle section 22, 23 focuses the jet of dye which can emerge from the capillary hole 24 formed between the wire and the tube.

The tube section 16 can engage with the sealing rings 25 and fit. into the holder with a slight clamping action so that the position of the pen with respect to the debouchment of the narrow hole 17 can be adjusted in the axial direction.

The embodiment shown in Figure 5 is an actual embodiment which is preferred and which is shown on a scale of 4:1. The parts which correspond to those shown in the previous figures have the same reference numerals.

The holder, indicated here by 26, has a somewhat different shape and is to some extent L-shaped in side view so that a limb 27 is formed which contains the air supply channel 28 with connecting cone 29 for a flexible air tube. The hole 28 merges via a short part 30, inclined a t an angle, into the second hole 20 upstream of the ball valve 11.

This achieves the result that the air connection extends parallel to the pen and as a result of this is not in the way during drawing. In this embodiment, the diameter of the first hole at the point where the section 16 of the pen is received is 3 mm and is consequently matched to the standardized dimension of drawing pens obtainable commercially.

Claims

CLAIMS 1. Contact-free drawing pen consisting of a holder for receiving a drawing pen with a dye reservoir and a writing p e n, communicating with the dye reservoir via a capillary, of the type consisting of a tube and a wire which projects with axial play therein and is capable of limited movement and which may project out of the end of the tube, which holder is provided with a connection to a source of medium under pressure, with a jet nozzle which engages with the writing pen, and with a valve which can be operated manually and which is in communication between the pressure medium connection and the jet nozzle, characterized in that the holder has a first through hole having a first part for receiving the housing of a drawing pen in a sealed manner and detachably therein, a second part of smaller diameter which concentrically surrounds the tube of the writing pen with play, and a third part, situated between said parts, which is in communication with a second hole whose centre line crosses that of the first hole and in which there is, at a distance from the first part of the first hole, an axially moveable valve which is under spring pressure in the pressure medium supply which engages with an operating pin and which extends tranversely through the third part of the first hole and projects outside the holder on the side facing away from the valve and engages at that point with an operating element.

2. Drawing pen according to Claim 1, characterized in that the valve is a ball valve and the valve seating is an O- ring.

3. Drawing pen according to Claim 1 or 2, characterized in that the channel in the holder for supplying the pressure medium to the second hole may extend essentially parallel to the centre line of the first hole.