CONTACT-FREE DRAWING PEN (''AIR-BRUSH'')

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 dra ng 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, com¬ municating 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 lim ted movement and w ich may project out of the end of the tube, which holde is provided with a connection to a source of medium under pressure, with a jet nozzle w ich engages with the wri in pen, and with a valve which can be operated manually and which is in communicat on 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 o a holder in which it is possi le to place a drawing pen o 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 car ries a valve, which' can be operated with a finger, in a ho extending parallel to the centre line of the felt pen, whi hole is connected, on the one hand, to a pressure medium source and, on the other hand, to a nozzle whose centre I * - makes an angle with the centre line of the felt tip, which hole is pro ded downstream of the valve with an adjustabl throttling element which has to do service in ac ieving a fine adjustment of the quantity of air which can spray via the nozzle onto the point of the felt tip. If this is don the stream of gaseous medium, such as compressed air, emer ing from the nozzle ensures that the dye particles a r e re¬ moved from the felt tip and dispersed in the form of a spr In t is manner it is c ; * ■ ? b I e 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 ion of the pen on the surface. A disad antage of said known contact-free drawing ith felt tip is that, as a result of d rec ing the j t 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 sai publication, instead of the felt tip it is also possible t 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 capable of projecting somewhat out thereof and which is to some extent oveable with res-pect to the tube. Said know 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 th tube end. If such a pen known per se is used in the holde drawn and shown for felt tips, it is equally impossible to produce a precise delineation by means of lines and areas the surface to be processed, such as the paper, as a resul of the angled position of the jet of medium with respect t the centre line of the writing pen section. In addition, the valve operation has the drawback any valve which is forced into the closed position by the pressure medium and has to be opened against the force of spring and also of the pressure med um. As soon as openin has taken place, the force of the pressure medium is large eliminated. The operating f ' inger then experiences a diffe ent counter pressure and, with inadequate compensation of spring pressure, t s makes t d fficult to control the qu i y of air which emerges. This is the reason why said kno pen is provided with a throttling element, situated down¬ stream of the valve, with wh ch the passage of the quaπtit med um allowed through the valve can be increased or de¬ creased and with which it is ntended to br ng about a reg latioπ of the outward flow of pressure edium from the jet nozzle of the pen without compensation of the spring press To perform such a regulation the dra ing operation has to interrupted. Said known pen is fairly bulky. The holder sec¬ ion for receiving the pen and the house forming a whole at t is point for valve, throttl ing element and jet nozzl are larger than the p n i tself. The known pen does have the advantage that it is p-qssible to change pen, and consequently colour, at any instant without anything ha ing 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 ha ing a regulating needle, to which nozzle pressure medium and dye are con¬ centrically fed and with which both the quantity of press medium and also the quantity of dye are therefore regulat ith said pens based on the paint spray principle, a bett defined spray can be produced than in the case of angled blo ing and good delineation of the areas concerned or sharp lines can therefore be achieved. In addition, said known drawing pen has the draw¬ back that the construction is relatively expensive and th 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 t risk of damage, in particular if fine sizes are involved. The object of the invention is therefore to pro- vide a contact-free drawing pen which h.as the advantages of the pen as it is known from the European Patent Appl i¬ cation 0,092,359, but lacks the disadvantages thereof, as well as the disadvantages of pens which a r e based on the pa int spray principle, and w i h is light and v e r y compact in construction and can be manufactured xj r cheaply. In addi ion, the object of the inven ion is to provide a pen which is very easy to handle and can be very satisfac¬ torily controlled. According to the invention this object is ach ieved in that the holder has a first through hole having a f irst part for receiving the housing of a dra ing pen in a seale manner and detachable ... -ein, a second part of smaller dia eter which concentrically surrounds the tube of the writing pen with play, and a t ird part, situated be¬ tween said parts, which is in communication with a sec¬ ond 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 oveable valve which is under spring pressure in the pressure medium supply, which engages with an operating pin and which extends transverse¬ ly 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 dia¬ meter, 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 pos- tion 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 conta ns the control section, and the control ele¬ ment of the valve crosses the pen section, an extremely com pact and consequently also airtight construction is obtaine The valve, which is preferably constructed as a ball valve which engages with an 0-ring, can be given such small dimen ions that the pressure drop across the valve hen opens no longer plays any part in controlling the quant ty to be allowed through so that a very precise control can be achieved with one s ngle valve and operating element. Accord ng to the invention, the channel in the holder for supplying the pressure medium to the second hole may extend essentially parallel to the centre l ine of the f i r s h o l e . This achieves the result that the pressure mediu supply is not in the way when the pen is being handled. The invention will no be explained in more detai 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 111-111 of Figure 1. Figure 4 is a section along the line IV-IV of igure 2 Figure 5 is a section through an embodiment which i s 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 t housing 2 and the cylindrical part 3, which contains the writing pen section and which is inserted in a hole of th holder 1, can be seen. At 4 there is a tube connect on for attac ing a flex ble tube 5 which can be connected to a reservoir, no shown, containing compressed air which is known per se. Holder 1 has an operating element 8 which rests o the end 10 of the operating pin of the valve not shown in Figure 1, which valve is shown in exploded form in Figure and consists of the ball 11, the 0-ring 12 and the hold-d spring 13. The connecting nipple 4 is shown hero -j π 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 en¬ gages wit the 0-π ' ng 12 and which is held in i s closed position by the light spring 13. Said spring rests agains the nipple 4 The operating pin 10 is guided in the narro er, hole section 21 and projects through the chamber 18 and is in contact with the ball 11. From Figure 3 it clearly follows that f the pin 10 is pressed downwards, the ball will be forced off the 0-ring 12 and will permit a commuπi cation 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 ire 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 a al direction. The embodiment show ' n in Figure 5 is an actual em¬ bodiment 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 -shaped in side view so that a limb 27 is formed w ich contains the air supply channel 28 with connecting " cone 29 for a flexible air tube. The hole 28 merges via a short part 30, in¬ clined a t an angle, into the second hole 20 upstream of the ball valve 11. This achieves the result that the air connection e tends parallel to the pen and as a result of this is not i the way during drawing. In this embodiment, the diameter the first hole at the point where the section 16 of the pe is received is 3 mm and is consequently matched to the sta dardized dimens on of dra ing pens obtainable commer ally.

Claims: AMENDED CLAIMS [received by the International Bureau on 09 February 1988 (09.02.88); original claim 1 amended; new claim 4 added; other claims unchanged (1 page)] 1. Contact-free drawing pen 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 Cube and a wire which projects with axial play therein and is capable of limited movement and which may aproject 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 can be operated manually and. which is in communication between the pressure medium connecting and the jet nozzle, characterized in that the holder (1) has a first through hole (15) having a first part for receiving the housing (16) of a drawing pen (2,3) in a sealed manner and detachably therein, a second part (17) of smaller diameter which concentrically surrounds the tube (22) of the drawing pen with play so as to enable the pressure medium to flow concentrically around the dye entrained from the pen, and a third part (18), situated between said parts, which is in communication with a second hole (19) whose centre line is perpendicular that of the first hole (15) and in which there- is, at a distance from the first part of the first hole (15), an axially moveable valve (11) which is under spring pressure in the pressure mexium supply, which valve cooperates with an operating pin (10) and projects outside the holder (1) at that point cooperates with an operating element. 2. Drawing pen according to calim 1, characterized in that the valve (11) is a ball valve and the valve seating (12) is an 0-ring. 3. Drawing pen according to claim 1 or 2, characterized in that the channel (30) in the holder for supplying the pressure medium to the second hole (19) may extend essentially parallel to the centre line of the first hole (15). 4. Drawing pen as calimed in claim 1, characterized in that the outer front wall of the holder surrounding the mouth of the cylindrical second part (17) of the first hole (15), over its entire surface lies in a plane perpendicular to the axis of the hole (15,17) with a 90° sharp angle between the front roll and the inner wall of the hole.

Inventors: GIELISSE GIJSBERTUS MARIA THEO, GIELISSE, GIJSBERTUS, MARIA, THEODORUS
Applicants: GRAFIC WORLD V O F, GRAFIC WORLD V.O.F.
Application year: 1987
Main classification: B05B7
IPC codes: B05B7, B41J2, B43K8