EP0044038A1 - Hand-held apparatus for electrostatically flocking objects - Google Patents

Abstract

1. Hand-held apparatus for electrostatically flocking objects, in particular for applying short textile fibres to surfaces covered with adhesive, the apparatus comprising an applicator (8) of beaker-like shape for accommodating the flock material, a high voltage electrode (7) arranged in the beaker (23) and a high voltage generator (1), wherein the high voltage generator is arranged in a plastic housing (16), which simultaneously serves as the carrier for the applicator, and is fed from a d.c. source (13), and wherein the plastic housing (16) is bar-shaped and serves to accommodate a high voltage transformer (4) fed by an oscillator (3), characterized in that the bar-shaped plastic housing (16) is connected with a likewise bar-shaped metallic or metallized housing (15) ; in that the metallic or metallised housing (15) forms a receptacle for batteries (13) provided as the d.c. source and has an earth connection (14) ; and in that, starting from the d.c. side, an oscillator (3), a transformer (4) and a cascade circuit (5) with a protective resistor (6) are arranged as the high voltage generator (1) in the bar-shaped plastic housing (6).

Description

The invention relates to a hand-held device for electrostatically flocking objects, in particular for applying short textile fibers to surfaces provided with adhesive.

In electrostatic flocking, short fibers, in particular textile fibers, are applied to any surface with the formation of a velvety surface, the connection of flock material and surface being permanently ensured by an electrically conductive adhesive applied beforehand.

The adhesive materials can be applied by brushing, spraying, screen printing and the like and, depending on the requirements, consist of one- or two-component systems. The flock materials usually consist of viscose, polyamide, polyester or cotton, the length of the individual fibers being approximately in the range from 0.5 mm to 3 mm.

Known flocking devices generally work with direct charging of the flock material to a relatively high voltage, for example above 10 kV, in which case the electrostatically charged fibers of the flock material to the object to be flocked by the electrostatic attraction of the charged particles through the grounded surface of the object to be flocked be transported.

The flock material can be charged with DC voltage or pulsed high voltage, for example. Known devices that operate on the basis of this charging principle require the supply of a rectified high voltage or pulse voltage, which has been transformed up from the mains voltage, to the flocking device, which requires complex, voluminous and fault-prone power supply units and high-voltage lines that require special safety measures.

The object of the invention is to provide a hand-held device for electrostatically flocking objects, which avoids the disadvantages described above, -: has a compact structure, is not subject to any restrictions with regard to the place of use and ensures simple and reliable handling.

This object is achieved according to the invention by a cup-shaped applicator intended to hold the flock material and having a high-voltage electrode attached to the bottom and a high-voltage generator which is arranged in a plastic housing which also serves as a carrier for the applicator and is fed from a direct current source.

Since all components required for high-voltage generation are integrated in the hand-held device and the required low DC voltage can be supplied by commercially available batteries, a hand-held device which is easy to handle, can be used practically in any areas and applications and is not susceptible to faults.

The batteries are preferably arranged in a metal housing connected to the plastic housing of the high-voltage generator and having a ground connection, and it is particularly advantageous in the practical implementation of a hand-held device according to the invention that the plastic housing receiving the high-voltage generator and the metal housing receiving the batteries are rod-shaped and to connect these two housings to one another in a fixed or detachable manner. This creates a particularly compact and easy-to-use flocking device.

The high-voltage generator housed in the rod-shaped plastic housing comprises an oscillator, which can preferably be connected to the direct current source via a pushbutton switch, a transformer and a cascade circuit with protective resistor. The oscillator, which is supplied, for example, with a DC voltage of 4.5 volts, which can be supplied by three cylindrical batteries connected in series, generates a high-frequency AC voltage in the range from 8 to 50 kHz, which is supplied via a high-voltage transformer, which is preferred is equipped with a ferrite rod core, is fed to a multi-stage high-voltage cascade, at the output of which the required high voltage of, for example, 30 to 100 k \ is available.

The high-voltage cascade is preferably constructed from ceramic capacitors in stack form and Si diodes, since in this way an arrangement which is particularly suitable for accommodation in the rod-shaped housing is obtained. However, it is possible in the same way to construct the cascade circuit from axially parallel, series-connected plastic film capacitors and grid-type Si diodes.

A high-voltage terminating resistor which simultaneously forms the protective resistor limits the short-circuit current to the permissible value.

The high-voltage electrode is arranged on the bottom of the cup-shaped applicator and connected directly to the output of the high-voltage generator via a plug or screw pin, so that the applicator can also be exchanged without problems by loosening this plug or screw connection.

Although the high-voltage electrode can be disk-shaped, plate-shaped or ring-shaped and can be provided with tips to increase the corona, it is preferred as a high-voltage electrode, a rectangular or square plate with ends bent up to form tips is used, which covers the bottom of the cup, leaving an edge area free.

In the exposed edge region of the cup, a plurality of pull holes are preferably provided, by means of which it is possible to remove the electron wind which is caused by the electrode. given electrons is generated, noticeably amplified and to ensure a particularly uniform and vortex-free transport of the flock material.

The draw holes are preferably provided with a fine-mesh cover, in particular made of a fabric.

A cover in the form of a plastic grille cover is also provided for the applicator opening, this plastic grille cover not only preventing the flock material from falling out, but at the same time helping to break up or break up any flock material clumps.

According to a particularly advantageous embodiment of the invention, the applicator consists of at least two nested plastic cups which are fixed relative to one another, the rod-shaped plastic housing containing the high-voltage generator extending through the outer cup bases to the bottom of the cup having the high-voltage electrode and serving to hold the flock material. Two cups are expediently put together to form an applicator, the outer cup, which has a corresponding central opening, being pushed over the cylindrical plastic housing and thus contributing to the stable guiding or holding of the applicator. If the applicator consists of several nested cups, pull holes are provided in all of the bases of these cups, which are preferably offset from one another.

To further improve the ease of use and to enable control of the operational and operational readiness, according to a further development of the invention, a control circuit containing at least one optical signal element can be connected in parallel to the direct current source via a switch, the control circuit containing the optical signal element preferably having at least one diode and a limiting resistor contains.

With these simple means, charge control of the batteries on the one hand and a switch-on control of the device on the other hand are realized.

A zener diode is preferably provided as the diode, the zener voltage having to be adapted to the lower limit voltage of the direct current source, the voltage being e.g. on the light emitting diode must be taken into account. If several diodes are connected in series instead of a zener diode, the number of diodes is selected such that the sum of the forward voltages of the individual diodes is adapted to the lower limit voltage of the direct current source. If the voltage of the batteries forming the direct current source drops below a certain value, then no more current can flow in the control circuit and the optical signal element goes out and thus signals an insufficient charge of the batteries.

The switch assigned to the control circuit can be actuated at least via the switch on the hand flocking device and in particular the control circuit is connected to the contact of the switch on the device connected to the high voltage generator. In this way, when the batteries are sufficiently charged, it flows during operation also in the control circuit the current defined by the limiting resistor, so that the optical signal element, which can consist of a light-emitting diode or an incandescent lamp, signals the switched-on state.

• Fig. 1 eine schematische Längsschnittansicht einer Ausführungsform eines Handbeflockungsgeräts nach der Erfindung,
• Fig. 2 eine schematische Vorderansicht des Applikators des Geräts nach Fig. 1,
• Fig. 3 eine schematische Schnittansicht des im Gerät nach Fig. 1 vorgesehenen Hochspannungstransformators,
• Fig. 4 eine schematische Darstellung einer Ausführungsform einer Hochspannungskaskade, wie sie beim Gerät nach Fig. 1 eingesetzt werden kann,
• Fig. 5 eine schematische Darstellung der aus mehreren in einem stabförmigen Gehäuse angeordneten Batterien bestehenden Gleichstromquelle mit erfindungsgemäßem Kontrollkreis, und die
• Fig. 6 und 7 schematische Darstellungen von weiteren Ausführungsformen eines Kontrollkreises nach der Erfindung.

The invention is explained below using an exemplary embodiment with reference to the drawings; in the drawing shows:

• 1 is a schematic longitudinal sectional view of an embodiment of a hand flocking device according to the invention,
• 2 shows a schematic front view of the applicator of the device according to FIG. 1,
• 3 shows a schematic sectional view of the high-voltage transformer provided in the device according to FIG. 1,
• 4 shows a schematic representation of an embodiment of a high-voltage cascade, as can be used in the device according to FIG. 1,
• 5 shows a schematic illustration of the direct current source with a control circuit according to the invention consisting of several batteries arranged in a rod-shaped housing, and FIG
• 6 and 7 are schematic representations of further embodiments of a control circuit according to the invention.

In the hand flocking device shown in FIG. 1, a high voltage identified by the general reference number 1 is in a rod-shaped or tubular plastic housing 16 arranged generator, which consists of an oscillator 3, a transformer 4 and a high-voltage cascade 5 with terminating or protective resistor 6. The individual stages of this high-voltage generator 1 are still explained.

The high-voltage generator 1 is supplied from a direct current source which is formed by three cylindrical batteries 13 connected in series, which are arranged in a metal tube 15 which has essentially the same diameter as the plastic tube 16 and is either fixedly or releasably connected to it . At the end, the metal tube 15 can be closed by means of a screw cap, as is customary, for example, with pocket torches. On this metal housing 15, a ground connection 14 is also provided for a line for connection to the object to be flocked. A key switch 2 is switched on in the electrical connecting lines from the direct current source to the oscillator 13.

The output of the high-voltage generator is connected to a high-voltage electrode 7, which is arranged on the bottom of a cup-shaped applicator 8. The connection is expediently made via a plug-socket arrangement 25, 26, so that a convenient separation of applicator and high-voltage generator is possible at any time and, accordingly, different applicators can be used in a simple manner.

The applicator 8 consists of two nested plastic cups 22, 23, wherein the outer cup 22 can be closed with a cover 9 designed as a grid, so that a receiving space for the flock material 10 is defined.

The inner cup 23, the height of which is significantly less than the height of the outer cup 22, is firmly connected to the latter, for example at an adhesive area 24.

The rod-shaped plastic housing 16 extends through the bottom of the outer container 24. In this way, the applicator 8 is guided and securely held with respect to the rod-shaped housing 16.

Both at the bottom of the inner cup 23 and at the bottom of the outer cup 22 there are several, preferably uniformly distributed draw holes 11, which are covered by a fine-mesh grid 12. The draw holes 11 of the inner cup 23 lie in the edge area between the electrode 7 and the cup side wall and in the radial direction outside the draw holes 11 of the outer cup 22.

The applicator 8 and also the rod-shaped housing 16, in which the high-voltage generator 1 is located, can consist of PE material.

For flocking, the applicator 8 is filled approximately halfway with flock material 10 and guided at a distance of approximately 10 to 20 cm to the flocking object 27 which is provided with electrically conductive adhesive and contacted with an earth line. When the high voltage is switched on, the flock particles become negative, e.g. to about 30-100 KV. charged and fly supported by the developing electron wind towards the grounded object 27. Do it yourself. the particles emerge like arrows and penetrate into the adhesive due to their kinetic energy, where they are permanently anchored when the adhesive hardens.

FIG. 2 shows the applicator 8 according to FIG. 1 consisting of two nested cups 22, 23 in a front view. It can be seen that the high-voltage electrode 7 is essentially square, the bent corners forming peaks that lead to an increase in the corona. In the corner areas in this case rectangular in cross section or square-shaped applicator, the pull holes 11 are provided, which are covered with a fine-mesh grid 12. The correspondingly offset draw holes 11 of the outer cup 22 are indicated by dashed lines.

Instead of an applicator that is rectangular or square in cross section, an applicator that is circular in cross section can also be used, with no differences in terms of function.

3 shows an embodiment of a transformer which can be used in high-voltage generator 1 and which consists of a ferrite rod 17, on which the primary winding consisting of relatively few turns and optionally a feedback winding are attached and fixed, for example, by means of a double-sided adhesive tape. The secondary winding 19 is accommodated in a bobbin core 18 provided with chambers and has a relatively high number of turns. The number of turns of the secondary winding is expediently in the range from 5000 to 10000 turns.

The output voltage of the transformer is fed to a high-voltage cascade, as shown for example in FIG. 4. This cascade circuit is preferably also rod-shaped and constructed from capacitors 20 and diodes 21. The capacitors can be designed as ceramic capacitors or plastic film capacitors.

A Cernet-based resistor, which is also used as a protective resistor, is preferably used as the high-voltage terminating resistor 6. resistor chain can be designed in the form of several resistors and limits the short-circuit current in the necessary manner.

Fig. 5 shows a rod-shaped, metal or at least metallized housing 15, which serves to hold batteries 13 and is fixed or detachably connected in the manner already described with a plastic tube which carries a cup-shaped applicator. The rod-shaped housing 15 can be closed by means of a screw cap, as is customary, for example, in the case of rod flashlights. One pole of the batteries 13 is connected to the housing via a spring 28. The other pole 29 of the batteries 13 is guided to a contact of a switch 2, which, when activated, i.e. closed switch is connected to the line 31 leading to the high voltage generator. The switch 2 is formed in practice by the "ON" button of the flocking device.

A control circuit, which is formed by a light-emitting diode 30, a zener diode 33 and a limiting resistor 34, is connected between the line 31 leading to the high-voltage generator and the negative pole of the direct current source. This control circuit is accordingly on the one hand electrically connected to the switch or push button contact 32 and on the other hand to the housing 15.

The Zener voltage of the Zener diode 33 is selected in accordance with the lower limit voltage of the battery 13, that is to say that the light-emitting diode 30 can fulfill a double function in such a way that it simultaneously guarantees a charge control and a switch-on control. In an illustrated embodiment, both functions can be checked during operation of the probe 2, but it is in the case of use of two separate switch or button or sequentially zuzuschaltender contacts also possible for the two functions to be switched separately, and thus the warning device of the Ladun ^g skontrolle to be carried out separately.

In the embodiment variant shown in FIG. 6, at least one diode 35 is used instead of a zener diode. Since a voltage level of 0.7 V is assigned to a diode, several diodes 35 'may have to be connected in series.

FIG. 7 shows that a lamp 36 can also be used instead of a light-emitting diode 30, as has been shown in FIGS. 5 and 6. It is indicated in FIG. 7 that the solutions already described above with zener diode 33 and at least one diode 35 can also be implemented in connection with such a lamp 36.

All of the solution variants shown according to the invention are characterized by simplicity and operational reliability and can be implemented in practice with minimal effort.

Claims (29)

1.Hand-held device for the electrostatic flocking of objects, in particular for applying short textile fibers to surfaces provided with adhesive, characterized by a cup-shaped applicator (8) for receiving the flock material (10) with a high-voltage electrode (7) on the bottom and a high-voltage generator (1 ), which is arranged in a plastic housing (16) which also serves as a carrier for the applicator (8) and is fed from a direct current source (13). 2. Hand tool according to claim 1, characterized in that the direct current source (13) consists of batteries which are arranged in a with the plastic housing (16) and a ground connection (14) having a metal housing or metallized housing (15). 3. Handheld device according to claim 1 or 2, characterized in that the high voltage generator (1) consists of an oscillator (3) which can be connected to the direct current source (13), a transformer (4) and a cascade circuit (5) with protective resistor (6). 4. Hand tool according to one or more of the preceding claims, characterized in that the high-voltage generator (1) receiving plastic housing (16) is rod-shaped. 5. Hand tool according to claim 4, characterized in that the batteries (13) receiving metal housing (15) rod-shaped and at least substantially with the same diameter as the plastic housing (16) and can be coupled thereto. 6. Hand tool according to claim 5, characterized in that between the batteries (13) and the high voltage generator (1), a switch, in particular a switch (2) is arranged and in the wall of the plastic housing (16) is held. 7. Hand tool according to one or more of the preceding claims, characterized in that the high-voltage electrode (7) is arranged on the bottom of the cup-shaped applicator (18) and is connected to the output of the high-voltage generator (1) via a plug-in or screw pin (25). 8. Hand tool according to claim 7, characterized in that the high-voltage electrode (7) disc, plate or ring-shaped and in particular is provided with tips. 9. Hand tool according to claim 8, characterized in that the _H ochspannungselektrode (7) consists of a rectangular plate with bent-up to form sharp corners exist. 10. Hand tool according to one or more of the preceding claims, characterized in that in the bottom of the cup-shaped applicator (8) a plurality of draw holes'. (11) are provided. 11. Hand tool according to claim 10, characterized in that the draw holes (11) are provided with a fine-meshed, in particular made of a fabric cover (12). , 12. Hand tool according to one of the preceding claims, characterized in that the applicator opening is provided with a removable plastic grille lid (9). 13. Hand tool according to one or more of the preceding claims, characterized in that the applicator (8) consists of at least two nested and relatively fixed plastic cups (22, 23), the rod-shaped plastic housing (6) containing the high-voltage generator (1). extends through the outer cup bottoms to the bottom of the cup (23) which has the high-voltage electrode (7) and serves to receive the flock material (10). 14. Hand tool according to claim 13, characterized in 'that the bottoms of the nested cups (22, 23) have a distance in the range of 5 to 80 mm. 15. Hand tool according to claim 13 or 14, characterized in that draw holes (11) are provided in all floors of the nested cups and in particular are arranged offset from one another. 16. Hand-held device according to claim 3, characterized in that the oscillator (3) which can be connected to direct voltage of, for example, 4.5 volts operates in the high-frequency range of approximately 8-50 kHz. 17. Hand tool according to claim 3, characterized in that the transformer (4) has a cylindrical ferrite rod core (7) on which the primary winding (28) consisting of a few turns is arranged, while the secondary winding (19) in chambers (18 ) a cylindrical plastic carrier is housed. 18. Hand tool according to claim 3, characterized in that the transformer is designed as a pot or toroidal transformer. 19. Hand tool according to claim 3, characterized in that the cascade circuit (5) from a stack of _K eramikkondensatoren (20) with Si-diodes (21) is constructed. 20. Hand-held device according to claim 3, characterized in that the cascade circuit (5) is made up of axially parallel, series-connected plastic film capacitors and a grid-shaped Si diode therebetween. 21. Hand-held device according to claim 3, characterized in that the protective resistor (6) forming the high-voltage terminating resistor consists of a cermet-based resistor. 22. Hand tool according to one or more of the preceding claims, characterized in that the components of the high-voltage generator (1) in the plastic tube (16) without voids with a high-voltage-resistant material. are shed. 23. Hand-held device according to one or more of the preceding claims, characterized in that a control circuit containing at least one optical signal element (30; 36) can be connected in parallel to the direct current source (13) via a switch (2). 24. Hand tool according to claim 23, characterized in that in the control circuit in series with the optical signal element (30; 36) at least one diode (33; 35) and a limiting resistor (34) are connected. 25. Hand tool according to claim 24, characterized in that a Zener diode (33) is provided as the diode. 26. Hand tool according to claim 24, characterized in that a plurality of diodes (35, 35 ') are connected in series. 27. Hand tool according to one of the preceding claims, characterized in that at least one light-emitting diode (30) or a lamp (36) is provided as the optical signal element. 28. Handheld device according to one or more of the preceding claims, characterized in that the switch (2) assigned to the control circuit can be actuated at least via the switch on the device. 29. Hand-held device according to one of the preceding claims, characterized in that the control circuit is connected to the contact (32) of the switch on the device connected to the high-voltage generator.

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