Flexible hose, in particular vacuum cleaner hose, method for producing the same and device usable therefor

Description

TECHNICAL FIELD

[0001] The present invention relates to a flexible hose according to the preamble of claim 1, as well as to a method for producing such a hose in large quantities and a device usable for this purpose. In particular, the invention relates to a flexible vacuum cleaner hose and its production, as used on a large scale in an industrial environment, in trades, and in private households. BACKGROUND OF THE INVENTION AND STATE OF THE ART

[0002] When very fine particles are sucked in or conveyed through a hose made of a plastic material such as polyethylene (PE), polypropylene (PP) or an ethylene-vinyl acetate copolymer (EVAC), for example using a vacuum cleaner, strong electrostatic charges are generated by the friction between the particles and the walls of the hose. These charges can discharge suddenly, possibly even with the formation of sparks, if the electrically charged suction hose comes into contact with a grounded component or operator. The discharges can be so strong that they can damage electronic devices and / or cause severe pain to the operator. In the worst case scenario, life-threatening situations arise, for example if a pacemaker is stopped.

[0003] In addition, spark discharges can ignite explosive dust / air, gas / air, or solvent vapor / air mixtures. An electrostatic ignition hazard can arise from both the charged material being conveyed and from charged components of the vacuum cleaner, especially the suction hose.

[0004] Such sudden discharges can be prevented if all parts of the vacuum cleaner that conduct particles are electrically connected to each other and to a protective conductor of the associated electrical connection for potential equalization.

[0005] Against this background, suction hoses made of a highly electrically conductive material, such as PE, into which fine soot particles are embedded, are increasingly being used to vacuum fine dust. However, this material is more expensive than pure PE and also leaves undesirable abrasion marks when the suction hose is pulled across a surface with its outer circumference. These abrasion marks can be prevented by applying an additional protective layer to the outer circumference of the hose, but this involves additional effort and further increases the cost of the suction hoses.

[0006] To remedy this situation, the publication DE 20 2009 016 596 U1 proposes the use of a coiled suction hose made of a cost-effective base material, on which at least one electrical conductor for dissipating electrostatic charge is provided, which extends essentially over the coil length of the suction hose, wherein the electrical conductor has a width that is at most equal to the passage width of the suction hose. This electrical conductor can be designed, for example, as a plastic layer with an embedded carbon black component, as a helically extending electrically conductive wire, or as an electrically conductive strip. Regarding the position of the electrical conductor, it can be seen from this prior art that the electrical conductor is either embedded in the material of the suction hose or arranged on the inside of the base of the spiral passage, on the outside of the base of the spiral passage, or inside or outside on the webs delimiting the spiral passage.

[0007] The publication DE 296 02 061 U1 discloses another electrically conductive hose with spirally extending wave crests on its exterior and adjacent wave troughs. An electrical conductor, covered on the outside, is inserted into the wave troughs. This conductor consists of an uninsulated stranded wire suitable for dissipating electrostatic charges. The electrical conductor is covered by a band made of thermoplastic material, the longitudinal edges of which are attached to the flanks of the wave crests by welding or gluing.

[0008] In order to enable, in particular, improved dissipation of electrical charges compared to the previously described hoses, which have a "simple electrically conductive device," WO 2005 / 047748 A1 further proposes a conveyor hose in which a combination of "two electrically conductive devices" is provided for dissipating electrical charges. One electrically conductive device is a region of the hose wall that concentrically surrounds the interior of the hose and is delimited by the inner surface. This region is provided with a significantly increased electrical conductivity compared to the base material by embedding electrically conductive particles in the base material.The other electrically conductive device is an axially extending, local electrical conduction element that is directly connected to the area of ​​increased electrical conductivity and is intended to conduct the charges collected by this area to earth.

[0009] In the pressure hoses according to this state of the art, the two electrically conductive devices are embedded directly into the hose wall during extrusion or co-extrusion of the respective pressure hose, so that a one-piece, ready-to-use pressure hose is created in a single operation.

[0010] In contrast, a preferred and widely used technique for producing flexible suction hoses, particularly with regard to good shape retention under an internal vacuum, consists in first extruding a profile from a plastic material, which is then wound helically or spirally, with adjacent windings or turns of the profile being welded or glued together. In this context, WO 2012 / 160524 A1, for example, discloses a flexible plastic hose produced by winding an extruded profile, wherein electrical conductors can also be embedded in the profile during the extrusion of the profile.

[0011] Furthermore, from the document DE 20 2017 107 890 U1, which forms the preamble of patent claim 1, a flexible hose is known which has an outer wall made from a plurality of turns of an extruded and helically wound profile. Adjacent turns of the profile are connected to one another by means of a seam, wherein the outer wall has an electrically conductive track which contains a conductive section of the extruded and helically wound profile and / or the seam. The conductive section consists of an electrically conductive plastic material. The electrically conductive track further contains an electrically conductive thread which, on the outer wall of the hose, is in electrical contact with the conductive section of the extruded and helically wound profile and / or the seam, embedded in the seam or a groove provided in the profile.This electrically conductive thread is also wound helically and is an integral part of the finished suction hose.

[0012] A disadvantage of the previously known electrically conductive, flexible hoses with "double conduction" is that in order to achieve good electrical conductivity of the hose, a relatively large amount of electrically conductive materials must be provided in the hose, which, due to their integration in the hose, are difficult to recover, if at all.

[0013] Furthermore, WO 2020 / 209352 A1 discloses a flexible hose with a base body, on whose outer circumferential surface a substantially strip-shaped conductive layer is applied, extending axially along the base body. The base body provided with the conductive layer is wrapped by a conductive wire spirally wound around the outer circumferential surface of the base body, which wire contacts the conductive layer. For protection, the conductive wire is covered by a reinforcing part that runs around the outer circumferential surface of the base body following the spiral winding of the wire in such a way that the surface of the conductive wire is "crimped" onto the outer surface of the conductive layer.

[0014] WO 97 / 16304 A1 further discloses a process for the continuous production of honeycomb structural materials of the "non-expanding type" from, for example, a thermosetting, resin-impregnated nonwoven fabric. In particular, this document relates to a process in which sequential and selective bonding occurs from node to node in successively applied, semi-cellular honeycomb layers. Bonding is preferably achieved using a tractor-type belt in the form of a toothed belt, which prepares or deforms a previously non-pre-corrugated web material and then consolidates it. As the toothed belt traverses the honeycomb surface during operation, it corrugates non-pre-corrugated web material between a front, contacting tooth of the belt and a counter-node of a previously laid web, which is surrounded and enclosed on its diagonally opposite flank sides by an uppermost row of forming rods.As the timing belt continues through the honeycomb, the initially "waved tooth" becomes a stationary consolidation tooth. In this section, the appropriately heated teeth of the timing belt are pressed against the forming bars using a pressurizing agent to consolidate the web material. The lower forming bars are then withdrawn, raised slightly, and inserted from above onto the last layer laid to repeat the process. This allows superimposed honeycomb structures of the desired height to be created.

[0015] Finally, document EP 2 378 174 A1 shows a flexible hose with a hose unit to whose inner wall a flexible tube is bonded by means of a heat-generating adhesive element. To manufacture the hose, the hose unit is first produced in a conventional manner, i.e., blow-molded or wound and cut to length. The tube is extruded and provided with the heat-generating adhesive element—consisting of a main body made of a meltable adhesive material and a heating wire. The heat-generating adhesive element is first attached longitudinally to the tube and then, using a holder, positioned together with the tube relative to the hose unit such that the heat-generating adhesive element is aligned opposite or on the inner surface of the hose unit.The heat-generating adhesive element is then activated by applying a voltage to the heating wire in order to thermoplastically bond the tube to the hose unit. TASK

[0016] Based on the prior art according to the document DE 20 2017 107 890 U1, the invention is based on the object of designing a flexible hose, in particular a vacuum cleaner hose, in such a way that the hose has good dissipation properties for electrostatic charges, while also addressing the problems mentioned above in relation to the prior art. In particular, the electrically dissipative, flexible hose should have improved suitability for recycling when a relatively small amount of electrically conductive materials is used. The object of the invention further includes specifying a method for producing such an electrically dissipative, flexible hose and a device for applying an electrically conductive thread to such a hose, which method / device enables the simplest, quickest and most cost-effective production and / orPartial assembly of the hose with at least one electrically conductive thread in large quantities is possible. DESCRIPTION OF THE INVENTION

[0017] These objects are achieved by a flexible hose, in particular a vacuum cleaner hose, having the features of patent claim 1, a method for producing a flexible hose having the method steps of patent claim 8, and a device for applying an electrically conductive thread to an outer side of a flexible hose having the features of patent claim 12. Advantageous embodiments of the invention are the subject of the dependent patent claims.

[0018] In a flexible hose, in particular a vacuum cleaner hose, which has a wall which, with an inner side, delimits a cavity for conveying media and has a profile at least on one outer side which, when viewed in section along a longitudinal axis of the hose, has a wave shape with elevations and depressions, wherein at least one electrically conductive track is provided on the outer side of the wall, which runs around the wall and is in electrical contact with at least one electrically conductive thread which electrically connects opposite ends of the hose; according to the invention, the electrically conductive thread is fastened to the outer side of the wall, running essentially along the longitudinal axis of the hose and transversely to the electrically conductive track.

[0019] In other words, the electrically conductive thread—unlike in the prior art discussed above—is not laid in the circumferential direction of the hose, but rather extends in the longitudinal direction of the hose according to the invention, crossing the circumferential electrically conductive path under an electrical contact, thus effectively short-circuiting it electrically. Electrostatic charges collected in the electrically conductive path as a "first electrically conductive device" are thus directly conducted to the ends of the hose via the electrically conductive thread as a "second electrically conductive device."

[0020] Since the electrically conductive thread on the wall of the hose according to the invention does not encircle its longitudinal axis, but rather extends along or essentially parallel to the longitudinal axis of the hose when viewed from above, less electrically conductive material is required for this second electrically conductive device compared to the prior art described above. This is advantageous not only in terms of comparatively low electrical resistance, but also brings cost and weight advantages.

[0021] This possibility of influencing the electrical resistance of the hose by means of the electrically conductive thread designed or arranged according to the invention can, depending on the desired or required electrical conductivity, also allow the individual resistances of the web and thread to be distributed differently, for example by reducing the electrical conductivity of the electrically conductive web, e.g. by reducing the carbon black content in a plastic material for the electrically conductive web that has been made electrically conductive by adding carbon black, which also offers cost advantages.

[0022] Furthermore, since the electrically conductive thread is attached to the outside of the wall, it is easier to remove the electrically conductive thread of a hose to be disposed of from the rest of the hose for recycling purposes - again in comparison to the prior art discussed at the beginning, in which all electrically conductive devices are integrated into the hose, more precisely its wall.

[0023] Last but not least, the inventive design of the hose advantageously allows for a (at least) two-step process during its production, in which a base hose is first produced with the electrically conductive web as the first electrically conductive device. Only in a second step is this base hose refined by applying the electrically conductive thread as the second electrically conductive device with a view to improved electrical conductivity. As a result of this modular design of the hose, it is possible to produce hoses with different electrical conductivity levels from a type of modular system, depending on the desired or required properties. This ensures high flexibility in hose production and also offers cost advantages.

[0024] The term "electrically conductive thread" refers, in its most general sense, to an electrical conductor whose longitudinal extension is much greater than its width and thickness. In principle, the "thread" can also be both an electrical conductor and a fastening element, as is the case, for example, with a narrow, electrically conductive adhesive tape or an electrically conductive adhesive applied in a narrow, longitudinal track. Depending on the type of solidification, this adhesive may be a two-component or multi-component adhesive, an adhesive that reacts under visible or UV light, or a thermoplastic adhesive (hot melt adhesive).

[0025] If the electrically conductive thread and its fastening means are two components, it is generally possible to apply the electrically conductive thread to the profile of the hose and to laminate or coat it during or after the process, e.g. using a hot melt adhesive, a UV adhesive or UV varnish, or a track made of a suitably reacting or curing plastic foam or casting resin. In contrast, particularly with regard to cost-effective and process-reliable production, it is currently preferred for the electrically conductive thread to be attached to the outside of the wall using an adhesive tape. In an expedient embodiment, the adhesive tape can cover the electrically conductive thread on both sides, viewed in the circumferential direction of the hose, which promotes the best possible contact between the electrically conductive thread and the electrically conductive track.

[0026] Furthermore, it can be provided that the electrically conductive thread or the adhesive tape covering the electrically conductive thread is surrounded on the outside of the wall - possibly as a further refinement - by a braiding of the hose. In this case, the braiding can advantageously serve as (additional) securing and / or as (further) protection of the electrically conductive thread on the outside of the wall of the hose. With a suitable design of the device for braiding the flexible hose, it is also possible to apply and fasten the at least one electrically conductive thread to the outside of the wall during braiding. A combination of fastening the electrically conductive thread using an adhesive tape and braiding the hose is particularly suitable when the application of the electrically conductive thread and the braiding take place at different locations and / or at different times.

[0027] In principle, it is possible to provide the electrically conductive path at any location on the outside of the hose wall, as long as it is ensured that the at least one electrically conductive thread can electrically contact and short-circuit the electrically conductive path. However, particularly with a view to ensuring the easiest and most reliable contacting of the electrically conductive path by the electrically conductive thread, it is preferred if the electrically conductive path is formed on the outside of the wall near or at the elevations of the profiling.

[0028] In a suitable embodiment of the flexible hose, it can further be provided that the hose is provided on one or both of the opposite ends with a hose receiving piece made of an electrically conductive material, if necessary also as an intermediate piece, which holds a further connecting part, e.g. a cone or a bayonet, on the finished hose to ensure proper hose connection to an associated end device (e.g. a vacuum cleaner) or tool, preferably in a rotatable manner. Electrostatic charges collected by the electrically conductive path of the hose and in particular passed on to the hose ends via the electrically conductive thread can then be transferred to the end device and its earthing and thus discharged or dissipated. If necessary.The hose receptacles and / or the connectors mounted thereon can also be provided with metallic contacts. With appropriate design of the hose receptacles and / or the connectors mounted thereon, electrostatic charges that arise, for example, during a grinding or polishing process on / in a grinding machine can also be advantageously discharged via the hose to an end device, such as a vacuum cleaner. This can be particularly useful if the machine itself does not have a grounded mains connection or is powered by compressed air or battery technology.

[0029] The following two variants are particularly suitable for attaching the aforementioned hose receptacles to the hose ends: In the first variant, if the external profile of the hose is helical, the end of the hose with the helical profile can be screwed into an associated internal thread section of the hose receptacle, wherein the electrically conductive thread is clamped between the profile and the internal thread section to form an electrical contact.

[0030] Such a design advantageously allows for the "refitting" of a defective hose, as may be desired by professional users, for example, by unscrewing the hose retainer from the defective hose, cutting off the defective or leaking hose section, and then screwing the hose retainer back onto the correspondingly shortened hose. A further advantage of this variant is that, when repairing the hose, reconnecting the electrically conductive thread to the hose retainer is particularly easy due to the aforementioned clamping of the electrically conductive thread between the hose profile and the internal thread section.

[0031] If such a repair option for the hose is not required or, for example, not desired to reduce manufacturing costs, the other variant can be used to insert the end of the hose into a dedicated receiving section of the hose receptacle and bond it to the hose receptacle using an electrically conductive adhesive, into which the electrically conductive thread extends, forming an electrical contact. It is of course also possible to implement both variants at the ends of one and the same hose if the hose is to be equipped with more than one type of hose receptacle.

[0032] In principle, the base hose can be formed, for example, by blow molding a suitable plastic material, optionally also with an electrically conductive web wound around the hose in a subsequent step. In contrast, it is preferred if the wall of the hose is formed entirely from a helically wound profile, with adjacent turns of the profile being connected to one another in a media-tight manner. The advantages of such a wound hose compared to a blow-molded hose are, in particular, that the hose can be formed with a substantially smooth inner surface and thus low flow losses and only low noise generation during operation. Due to the hose's good dimensional stability and resilience, higher suction capacities can also be achieved.

[0033] In a preferred embodiment of the wound hose, the adjacent turns of the profile are joined together in a media-tight manner using a hot-melt adhesive. This ensures reliable, fast, and cost-effective production of the base hose. However, other connection options, such as creating a material bond between the individual profile turns using laser welding, are also conceivable.

[0034] In terms of the method, the present invention provides a method for producing a flexible hose, which comprises at least the following three method steps a) to c): a) forming a base hose which has a wall which, with an inner side around a longitudinal axis, delimits a cavity and has a profile at least on one outer side which, when viewed in section, has a wave shape with elevations and depressions, wherein the wall is formed from an electrically conductive material or at least one electrically conductive track is formed on the outer side of the wall, so that the electrically conductive track runs around the wall; b) applying at least one electrically conductive thread to the outer side of the wall, so that the electrically conductive thread runs substantially along the longitudinal axis and transversely to the electrically conductive track;and c) attaching the electrically conductive thread to the outside of the wall so that the electrically conductive thread electrically contacts the electrically conductive track.;

[0035] The key here is the separation of the process steps a) forming the base tube on the one hand, and b) applying and c) attaching the electrically conductive thread to the outside of the wall on the other. This ultimately leads to the recycling advantages described above, because the electrically conductive thread subsequently applied / attached to the outside of the wall is generally easier to remove than a conductor that is an integral part of the base tube.

[0036] This separation of process steps a) on the one hand and b) or c) on the other hand also offers the advantage that, in the manner of a modular system, a hose of the same basic type, which does have the electrically conductive layer but does not (yet) possess increased electrical conductivity, can be further refined by applying / attaching the electrically conductive thread, depending on the respective electrical conduction requirements, or not, if this is not necessary or desired. It is also possible to further electrically equip a hose of the same basic type according to the respective requirements or wishes by applying / attaching various electrically conductive threads, which differ, for example, in type, material, dimensions and / or number.

[0037] As already mentioned above, a blow molding process can in principle be used in step a) of forming the base hose. However, particularly with regard to the simplest possible integration of the electrically conductive track in the hose, it is preferred if, in step a) of forming the base hose, a profile is first extruded from an electrically conductive plastic material or co-extruded from two plastic materials of different electrical conductivity, so that the profile comprises at least one electrically conductive track, after which the profile is wound helically to form the wall of the base hose, with adjacent turns of the profile being connected to one another in a media-tight manner. In this case, the adjacent turns of the profile are preferably connected to one another in a media-tight manner using a hot melt adhesive in a particularly process-reliable manner.

[0038] Steps b) of applying and c) of attaching the electrically conductive thread to the outside of the wall can also, in principle, be carried out sequentially, particularly when the electrically conductive thread and its attachment means are two distinct components of the hose. However, particularly with a view to achieving the fastest and most efficient production possible, it is preferred if steps b) of applying and c) of attaching the electrically conductive thread to the outside of the wall are carried out simultaneously, even if the electrically conductive thread and its attachment means are two distinct components of the hose.

[0039] After completing steps a) to c), the hose is already available as a semi-finished plastic product, which can optionally be delivered as a roll for further processing, e.g. to the manufacturer of an end device such as a vacuum cleaner. The preferred further processing of the hose can also be carried out by the hose manufacturer, e.g. immediately after production of the semi-finished plastic product, by attaching a hose holder made of an electrically conductive material to one or both of the opposite ends of the cut-to-length hose after step c) of attaching the electrically conductive thread to the outside of the wall, which makes electrical contact with the electrically conductive thread.

[0040] On the device side, according to the invention, a device is proposed for applying an electrically conductive thread to an outer side of a flexible hose, which is there, ieon its outer side has a profile which, when viewed in section along a longitudinal axis of the hose, has a wave shape with elevations and depressions, with the special feature that an applicator is provided for the electrically conductive thread, which has a rotatable, stick- or cell-wheel-like applicator wheel, on the outer circumference of which the electrically conductive thread can be fed and which is adapted to come into positive engagement with the profile of the hose which can be inserted in a hose support, so that when the applicator wheel rotates, a relative feed movement takes place between the hose and the applicator, in which the applicator wheel applies the electrically conductive thread along the longitudinal axis of the hose, following the elevations and depressions, to the profile of the hose.

[0041] The inventive design of the applicator wheel, which meshes with the profile on the outside of the hose in the manner of a rack and pinion drive, advantageously results in a forced coupling of the feed movement and the application or application movement for the electrically conductive thread. This ensures, on the one hand, that a corresponding or assigned length of electrically conductive thread is always deposited or applied per length of hose, which can be particularly beneficial for a uniform and / or tension-free application of the electrically conductive thread to the profile of the hose.

[0042] On the other hand, it is advantageous to use only one drive to generate both movements - relative feed movement to the hose and application or application movement for the electrically conductive thread. For example, the applicator can be moved actively relative to the hose or the hose relative to the applicator (relative feed), while the applicator wheel, as a result of the positive engagement with the hose, rolls passively on it and deposits the electrically conductive thread (application or application). It is also possible to hold the applicator stationary and actively drive the applicator wheel to rotate (application or application of the electrically conductive thread), whereby the hose is passively pulled away from under the applicator wheel as a result of the positive engagement between the applicator wheel and the hose's profile (relative feed).In addition, it is possible to design the applicator to be movable and to drive the applicator wheel actively in a rotating manner (application or application of the electrically conductive thread), so that the applicator with the applicator wheel moves passively with respect to the hose, which may be suitably held, due to the positive engagement between the applicator wheel and the profile of the hose (relative feed).

[0043] If at least two drives are provided, each assigned to the applicator, the applicator wheel or the hose, it is possible to further coordinate the generated movements with regard to the execution of the movement (speed, acceleration) using suitable electronics, for example in order to attach or apply the electrically conductive thread to the profile of the hose with little tension or particularly "loosely", i.e. with no tension.

[0044] One of the criteria for determining which components or assemblies of the device are stationary and which are movable is the length of the flexible hose to be provided with the electrically conductive thread. In the case of a hose as a roll or in continuous production, it is advisable, for example, to design the applicator to be stationary and, in contrast, to move the hose relative to the applicator. Particularly with regard to simple implementation of the application process for hoses of a defined length, a design of the device is currently preferred in which the hose support is fixedly attached to a frame of the device, wherein the applicator has an applicator carriage which carries the applicator wheel and is guided on the frame so that it can move along the hose support.

[0045] Furthermore, with a view to safe process control, it is also preferred if the applicator wheel is connected to a rotary drive so that the applicator wheel can be actively driven in rotation.

[0046] Furthermore, a preferred embodiment of the device is one in which the applicator has an applicator arm on which the applicator wheel is rotatably mounted and which can be pivoted relative to the hose support about an optionally lockable pivot axis. This makes it possible to use the device with its applicator for hoses of different thicknesses and / or basic shapes (e.g. cylindrical or conical on the outer circumference) without major conversion work. In the case of conical hoses, for example, the applicator wheel can easily follow the increasing or decreasing thickness of the hose over its length. By locking the pivot axis for the applicator arm, a certain contact pressure of the applicator wheel on the hose can be advantageously generated and adjusted by utilizing the inherent elasticity of the hose, for example in the case of a hose with a cylindrical outer circumference.

[0047] Preferably, the arrangement is further such that the applicator arm with the applicator wheel and its pivot axis is positioned relative to the hose support such that a torque results around the pivot axis in the direction of the hose support, and / or such that the applicator arm is resiliently preloaded around its pivot axis in the direction of the hose support. With such a configuration, the dead weight of the applicator arm with the components mounted thereon or its center of gravity relative to the pivot axis and / or the spring force acting on the applicator arm can be easily provided or selected such that the applicator wheel always bears against the hose with a defined pressing force when the electrically conductive thread is applied to the hose.

[0048] As mentioned at the beginning, it is generally possible to first position the electrically conductive thread on or in the profile of the hose using the applicator wheel and then attach it to the hose in a subsequent step, so that the electrically conductive thread is in permanent electrical contact with the electrically conductive track of the hose. However, particularly with regard to the highest possible throughput and high process reliability in hose production, it is preferable to apply and attach the electrically conductive thread to the hose simultaneously.For this purpose, a preferred embodiment of the device is one in which the applicator has a feed device for the electrically conductive thread and a feed device for an adhesive tape. The electrically conductive thread and the adhesive tape can be fed from the feed devices to a pair of guide rollers adapted to combine the thread and adhesive tape before being forwarded to the applicator wheel. This provides a simple way to ensure that the electrically conductive thread is precisely positioned and securely attached to the hose. Furthermore, the electrically conductive thread can be protected by the adhesive tape during application, for example, against excessive tension.

[0049] Finally, it is preferred if the applicator wheel has a plurality of axle pins evenly distributed around the circumference between two hub sections, each of which rotatably supports a hollow cylindrical sleeve as a pressure body for the electrically conductive thread. This measure also advantageously promotes mechanical relief of the electrically conductive thread during the application and attachment of the electrically conductive thread to the hose.

[0050] Further features, properties and advantages of the electrically conductive, flexible hose according to the invention, the method according to the invention for producing such a hose and the device according to the invention for applying an electrically conductive thread to a profiled outer side of a flexible hose will become apparent to the person skilled in the art from the following description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The invention will now be explained in more detail using preferred embodiments with reference to the accompanying, partially schematic drawings, in which identical or corresponding parts or sections are provided with the same reference numerals. In the drawings: Fig. 1 is a double-interrupted side view of a flexible hose, namely a vacuum cleaner hose, according to a first embodiment of the invention, which is provided with a hose receiving piece on both sides; Fig. 2 is a double-interrupted longitudinal sectional view of the flexible hose according to Fig. 1 ; Fig. 3 an enlarged view of detail III in Fig. 2 in a central area of ​​the flexible hose according to Fig. 1 ; Fig. 4 an enlarged view of detail IV in Fig. 2 at the Fig. 1 and 2 left hose receptacle of the flexible hose according to Fig. 1; Fig. 5 an enlarged view of detail V in Fig. 2 at the Fig. 1 and 2 right hose receptacle of the flexible hose according to Fig. 1 ; Fig. 6 an enlarged, fragmentary plan view of the flexible hose according to Fig. 1 , with view direction according to arrow VI in Fig. 1 , wherein an electrically conductive thread, attached to an outer side of the hose by means of an adhesive tape, for discharging electrostatic charges is shown in dashed lines; Fig. 7 is a simply interrupted, perspective view of a device according to the invention for applying the electrically conductive thread to the flexible hose according to Fig. 1 , obliquely from above / side left, with a view of an applicator for the electrically conductive thread in a starting position with respect to the tube; Fig. 8 a corresponding Fig. 7 simply interrupted, perspective view of the device according to Fig. 7from diagonally above / left side, where the applicator is in a middle position above the flexible tube; Fig. 9, again analogous to the Fig. 7 simply interrupted, perspective view of the device according to Fig. 7 from diagonally above / side left, with the applicator in a final position with respect to the flexible tube; Fig. 10 an enlarged view of detail X in Fig. 8 , to illustrate further details of the applicator of the device according to Fig. 7 ; Fig. 11 a side view of the device according to Fig. 7 , with a view to the one in the middle position corresponding Fig. 8 applicator; Fig. 12 a front view of the device according to Fig. 7 , looking from the right into Fig. 11 ; Fig. 13 a sectional view of the device according to Fig. 7 according to the offset section line XIII-XIII in Fig. 11; Fig. 14 a sectional view of the device according to Fig. 7 according to the section line XIV-XIV in Fig. 12 ; Fig. 15 a side view, broken off on both sides, of a flexible hose, namely a vacuum cleaner hose, according to a second embodiment of the invention, in which the hose is provided with a braid on its outside; Fig. 16 a longitudinal sectional view, broken off on both sides, of the flexible hose according to Fig. 15 ; and Fig. 17 an enlarged view of detail XVII in Fig. 16 in a central area of ​​the flexible hose according to Fig. 15 . DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] In the figures, a vacuum cleaner hose is generally designated by the reference numeral 10 as an example of a flexible hose. The hose 10 has, in particular, Fig. 2 to 5or 16 and 17, a wall 12, which defines a cavity 16 for conveying media with an inner side 14. On an outer side 18, the wall 12 has a profile 20, which, when viewed in section along a longitudinal axis 22 of the hose 10, has a wave shape with elevations 24 and depressions 26. As best shown in the Fig. 3 to 6 and 17 As can be seen, at least one electrically conductive track 28 is provided on the outer side 18 of the wall 12, which runs around the wall 12 and serves to collect and conduct electrostatic charges. As will be explained in more detail below, the electrically conductive track 28 is in electrical contact with at least one electrically conductive thread 30, which electrically connects opposite ends 32, 34 of the hose 10 in order to conduct the electrostatic charges thereto.

[0053] Here, the electrically conductive thread 30 runs according to e.g. Fig. 6substantially along the longitudinal axis 22 of the tube 10 and transversely to the electrically conductive path 28 or crossing the latter, wherein the electrically conductive thread 30 is attached to the outer side 18 of the wall 12, as shown in particular in the Fig. 3 to 5 and 17 can be seen. In these exemplary embodiments, the electrically conductive thread 30 follows the elevations 24 and depressions 26 of the profiling 20, with the thread 30 directly abutting the elevations 24 and - to establish electrical contact - of course, the electrically conductive path 28, while the thread 30 has a certain distance from the wall 12 in the region of the depressions 26. In comparison to a similarly possible "more stretched" course of the electrically conductive thread 30, for example, greater flexibility of the hose 10 can be achieved.

[0054] The illustrated embodiments are a wound, flexible hose 10, ie a hose 10 whose wall 12 is formed from a profile 36 wound helically around the longitudinal axis 22, wherein adjacent turns of the profile 36 are connected to one another in a media-tight manner. The profile 36 shown here as an example has two areas in cross-section, namely one in the Fig. 3 to 5 and 17 right-hand area, the cross-section of which essentially has the shape of the letter U in "square" notation and which forms the recesses 26 of the profiling 20 on the wound hose 10, and one in the Fig. 3 to 5 and 17 left-hand area, which, viewed in cross-section, essentially has the shape of a lying letter C or a letter tilted 90° clockwise and forms the elevations 24 of the profiling 20 on the wound hose 10. As shown in the Fig. 3 to 5 and 17As can be clearly seen, the C-shaped area of ​​a turn of the profile 36 is virtually "hooked" over the right leg of the U-shaped area of ​​an adjacent turn of the profile 36, so that there is a short profile overlap along the longitudinal axis 22. In the area of ​​this profile overlap, for example, a hot melt adhesive 38 is provided for the media-tight connection of the adjacent turns of the profile 36, which Fig. 3 to 5 and 17 shown, spiral-shaped seam.

[0055] From the Fig. 3 to 5 and 17 It can also be seen that the electrically conductive path 28 of the hose 10 is formed on the outer side 18 of the wall 12 near or on the elevations 24 of the profiling 20, namely as a partial region of the profile 36 which, in the wound state of the profile 36, also rotates helically around the longitudinal axis 22.

[0056] In the illustrated embodiments, the profile 36 is coextruded from two plastic materials of different electrical conductivity, so that the profile 36 comprises the electrically conductive web 28. A main part of the profile 36 can consist of a non-conductive plastic material, such as polyethylene (PE), polypropylene (PP), or an ethylene-vinyl acetate copolymer (EVAC), while the electrically conductive web 28 is formed from a conductive plastic material. The latter can, for example, be a PE, PP, or EVAC base material that is made conductive by the addition of conductive components, such as carbon black particles.

[0057] Alternatively, depending on the respective electrical conduction requirements, it is also possible to co-extrude the profile 36 entirely from such electrically conductive plastic materials, possibly even extruding it from the same material. In such a case, the profile as a whole, with its outer surface, forms the electrically conductive path.

[0058] As for the hot melt adhesive 38, this can also be made of a plastic material, such as PE or EVAC, which is either non-conductive or made conductive.

[0059] The term "electrically conductive thread" 30, as generally used here, is to be understood as meaning, on the one hand, a metallized thread, cord, or twine, e.g., an elastic twine made of a plastic, such as polyamide (PA), which is provided with a silver coating or a coating of copper, gold, or platinum, which promises very good conductivity, or a track or (adhesive) tape made of a plastic or resin that has been made electrically conductive, but on the other hand, also purely metallic conductors, such as wires or strands made of copper or the like, whereby the specific design of the electrically conductive thread 30 depends on the requirements placed on the hose 10, particularly with regard to its electrical and mechanical properties. For example,For a flexible hose 10 that is subjected to significant alternating bending or tensile stresses during use, it must be ensured that the electrically conductive thread 30 does not break or tear, or does not break prematurely. This tends to rule out the use of metallic conductors, which may be subject to cold-hardening, for such an application. Regarding electrical conductivity, there may be a requirement that the entire hose may only have a predetermined ohmic resistance, which can be achieved, for example, by appropriately selecting the electrically conductive thread 30.

[0060] As already mentioned above, at least one electrically conductive thread 30 is provided; i.e., depending on the respective requirements, several electrically conductive threads can also be provided, for example to reduce the electrical resistance in an overall arrangement and / or to provide a—possibly multiple—redundant overall arrangement. The electrically conductive threads 30 can run alongside one another or at least partially cross or overlap one another, making electrical contact. In such a case, the electrical connection of the opposite ends 32, 34 of the hose 10 and the electrical contacting of the electrically conductive track 28 are achieved by the overall arrangement of electrically conductive threads 30.In other words, it is in principle possible that none of the electrically conductive threads 30 of such an overall arrangement alone bridges the entire distance between the opposite ends 32, 34 of the hose 10, but the overall arrangement does, and / or only a part or one of the electrically conductive threads 30 of such an overall arrangement contacts the electrically conductive track 28.

[0061] Furthermore, in particular the Fig. 3 to 6 and 17 show, the at least one electrically conductive thread 30 is attached to the outer side 18 of the wall 12 by means of an adhesive tape 40 in the illustrated embodiments. Fig. 6The adhesive tape 40 can cover the electrically conductive thread 30 on both sides, as seen in the circumferential direction of the hose 10. The adhesive tape 40 is to be designed such that its adhesive side adheres reliably to the plastic material of the wall 12 or the profile 36. Suitable backings for the adhesive tape 40 include films, nonwovens, or fabrics made of a plastic material, such as PE, PP, polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyimide (PI), or polyurethane (PUR), depending on the application of the hose 10.

[0062] In the embodiment according to the Fig. 15 to 17Another special feature is that the adhesive tape 40 covering the electrically conductive thread 30 is surrounded by a braid 42 on the outer side 18 of the wall 12 of the hose 10. The braid 42 can consist of monofilament and / or multifilament threads made of a thermoplastic material, such as PA or PE. When the hose 10 is bent, the multifilament threads lie flat against the hose 10 on the tension side and compressed on the pressure side of the hose 10 transversely to the thread and thus also towards the wall 12 of the hose 10, so that the braid 42 always lies against the wall 12. With a particularly advantageous mixing ratio of 50% multifilament threads to 50% monofilament threads, the braided surface of the hose 10 also always remains closed.In an embodiment not shown here, the electrically conductive thread can thus be held in position on the wall by means of the braiding even without the adhesive tape covering it, whereby, of course, suitable placement of the electrically conductive track on the elevations of the profiling must ensure that the electrically conductive thread crosses the electrically conductive track under contact and thus makes contact.

[0063] The hose 10 described above can generally be produced as a roll by the hose manufacturer and delivered to, for example, manufacturers of relevant end devices, such as vacuum cleaners, where the hose 10 is then further assembled, which usually includes cutting the hose 10 to length and fitting the hose 10 with application-specific end pieces. However, it is also possible—and frequently the case—for the hose manufacturer to further assemble the hose 10.

[0064] In the Fig. 1 and 2 In the embodiment shown, the hose 10 is cut to length and provided at both of the opposite ends 32, 34 with a hose receiving piece 44, 46 made of an electrically conductive material, via which a targeted discharge of electrostatic charges to, for example, a terminal device and its grounding can take place. By way of example, in the Fig. 1, 2 , 4 and 5Two different types of hose receptacles 44, 46 are shown on one and the same hose 10. These hose receptacles 44, 46 can, if necessary, be connected to or provided with a further application-specific end piece (not shown), for example to provide a connection geometry adapted to the respective application, but often also to provide a relative rotation option between the hose receptacle and end piece. Such hose receptacles and end pieces are sufficiently known to those skilled in the art, so that only a brief description will be given below of how the respective hose receptacle 44, 46 is attached to the wall 12 of the hose 10 and how electrical contact is established between the electrically conductive thread 30 and the respective hose receptacle 44, 46.

[0065] In the Fig. 1 and 2The end 32 of the hose 10 with the helical profile 20 is screwed into an associated internal thread section 48 of the annular hose receiving piece 44 on the left-hand side of the hose 10, whose external profile 20 is helical as described above. Such a reversible screw connection has the advantage that, for example, if the hose 10 is damaged, the hose receiving piece 44 can be unscrewed, the hose 10 can be re-cut to length by removing the defective hose section, and then easily reassembled by screwing the hose receiving piece 44 back on. With this type of fastening, the electrically conductive thread 30 is clamped between the profile 20 and the internal thread section 48, forming an electrical contact. This is exemplified in Fig. 4shown on the left, where an end 49 of the electrically conductive thread 30 projecting beyond the adhesive tape 40 is clamped in this way.

[0066] In the Fig. 1 and 2 In the right hose receiving piece 46 of the hose 10, however, the end 34 of the hose 10 is inserted into an associated, here essentially hollow-cylindrical receiving section 50 of the annular hose receiving piece 46 and glued to the hose receiving piece 46 by means of an electrically conductive adhesive 52. As in Fig. 5 As indicated on the right with a dashed line, the electrically conductive thread 30 extends with an end 53 projecting beyond the adhesive tape 40 into the electrically conductive adhesive 52, forming an electrical contact.

[0067] A method for producing the flexible hose 10 described so far generally comprises the following three method steps a) to c): In a first step a), the formation of a base hose takes place, which comprises the wall 12, which with its inner side 14 around the longitudinal axis 22 delimits the cavity 16 and has at least on its outer side 18 the profiling 20, which, seen in section, has the wave shape with elevations 24 and depressions 26, wherein the wall 12 as a whole is formed from an electrically conductive material or at least the electrically conductive path 28 is formed on the outer side 18 of the wall 12, so that the electrically conductive path 28 runs around the wall 12. The base hose produced so far is in principle already ready for use, ieIf no special requirements are placed on it with regard to the ability to dissipate electrostatic charges, this basic hose can be manufactured by cutting it to length and providing it with suitable end pieces.

[0068] Only in a subsequent step b) when the hose 10 is subject to higher demands with regard to the dissipation of electrostatic charges is the at least one electrically conductive thread 30 applied to the outer side 18 of the wall 12, so that the electrically conductive thread 30 runs essentially along the longitudinal axis 22 and transversely to the electrically conductive path 28. In other words, in this step, the circumferential electrically conductive path 28 is short-circuited by means of the electrically conductive thread 30 or at least prepared for this purpose.

[0069] Finally, in order to maintain or bring about this electrical state during further processing and subsequent use of the hose 10, a further step c) involves attaching the at least one electrically conductive thread 30 to the outer side 18 of the wall 12, so that the electrically conductive thread 30 permanently electrically contacts the electrically conductive track 28. This attachment can, as already mentioned above, be achieved by applying or attaching the adhesive tape 40 and / or the braiding 42 to the outer side 18 of the wall 12 of the hose 10.

[0070] Preferred substeps of step a) of forming the base hose comprise, as also already mentioned above, a first substep in which the profile 36 is extruded from an electrically conductive plastic material or coextruded from two plastic materials of different electrical conductivity, so that the profile 36 has at least the electrically conductive web 28, if not is completely electrically conductive. Then, in a further substep, the profile 36 is wound helically to form the wall 12 of the base hose, with adjacent turns of the profile 36 being connected to one another in a media-tight manner, for example by means of the hot-melt adhesive 38, as is known per se.

[0071] With a view to rapid and efficient mass production of hoses 10, it is particularly preferred if steps b) of applying and c) of attaching the electrically conductive thread 30 to the outer side 18 of the wall 12 are performed simultaneously. A device that can be used for this purpose is described below.

[0072] After step c) of fastening the electrically conductive thread 30 to the outer side 18 of the wall 12, finally, at one or both of the mutually opposite ends 32, 34 of the hose 10 cut to length as desired or required, for example, the previously described hose receiving piece 44, 46 made of an electrically conductive material can be attached, which electrically contacts the electrically conductive thread 30.

[0073] The Fig. 7 to 14Details of a device 54 for applying an electrically conductive thread 30 (or several electrically conductive threads 30) to the outer side 18, for example, of the previously described flexible hose 10 can be seen. The device 54 has a frame 56, which in the illustrated embodiment is composed of aluminum profiles, on which the individual components or assemblies of the device 54 are arranged. As in particular the Fig. 7 to 9 show, the frame 56 is designed in the manner of a ladder frame, with two longitudinal profiles 58 which are firmly connected to one another by means of a plurality of transverse profiles 60.

[0074] On the cross profiles 60 of the frame 56 - see in particular the Figs. 7 and 8 on the left side or the Fig. 9on the right side - a hose support 64 is mounted on support profiles 62, which consists of an elongated angle profile with a V-shaped cross-section, which is attached to the support profiles 62 via fastening straps 66. As the Fig. 7 to 13 show, the hose support 64 serves to receive the hose 10 to be equipped with the electrically conductive thread 30, which moves automatically into a stable, lower end position in the hose support 64 due to the V-shape of the hose support 64.

[0075] The central component of the device 54 is an applicator 68 for the electrically conductive thread 30, which - as will be described in more detail below - has a rotatable, stick- or cell-wheel-like applicator wheel 70 (see the Fig. 10 and 12 to 14), to whose outer circumference the electrically conductive thread 30 is fed and which is adapted to enter into a positive engagement with the profile 20 of the hose inserted in the hose support 64. As a result, when the applicator wheel 70 rotates, a relative feed movement occurs between the hose 10 and the applicator 68, during which the applicator wheel 70 applies the electrically conductive thread 30 along the longitudinal axis 22 of the hose 10, following the elevations 24 and depressions 26, to the profile 20 of the hose 10.

[0076] In the illustrated embodiment, the arrangement is such that the hose support 64 is fixedly attached to the frame 56, while the applicator 68 has an applicator carriage 72 which carries the applicator wheel 70 in a manner to be described and - as will be seen in a comparison of the Fig. 7 to 9can be clearly seen - is guided on the frame 56 along the hose support 64 (see also the double arrow 74 for the longitudinal movement in the Fig. 10 , 11 and 14 ). For this purpose, the longitudinal profiles 58 of the frame 56 are each provided on their upper side with a continuous guide groove 76, in which a pair of profile sliders 78 slidably engage on each side of the frame 56, which in turn are firmly connected to the applicator carriage 72. The applicator carriage 72 itself is in the illustrated embodiment according to in particular the Fig. 10 to 14 in turn composed of a plurality of aluminum profile sections, one of which extends as a cross member 80 over the hose support 64.

[0077] The applicator 68 further comprises an applicator arm 82 on which the applicator wheel 70 is rotatably mounted in a manner to be described below and which can be pivoted relative to the hose support 64 about an optionally lockable pivot axis 84, which is best seen in the Fig. 11 and 14 can be seen (see also the double arrow 86 for the pivoting movement in these figures). For this purpose, the applicator arm 82 is articulated to the cross member 80 of the applicator carriage 72 with the aid of a joint 88 with a clamping lever 90. If the clamping lever 90 is locked, the applicator arm 82 is fixed in its respective angular position about the pivot axis 84. When the clamping lever 90 is released, however, the applicator arm 82 can pivot about the pivot axis 84.

[0078] According to Fig. 14 the pivot axis 84 and the applicator wheel 70 are located at opposite ends of the applicator arm 82. As further shown in particular in the Fig. 10 and 14As can be seen, the applicator arm 82 with the applicator wheel 70 and its pivot axis 84 is arranged relative to the hose support 64 in such a way that a torque in the direction of the hose support 64 results about the pivot axis 84, due to the weight of the applicator arm 82 and the components or assemblies mounted thereon. As a result of this torque, the applicator wheel 70 is pressed against a hose 10 placed in or on the hose support 64 and is held in engagement with its profile 20.

[0079] If necessary, the applicator arm 82 can also be manually pushed toward the hose 10 and then secured in this pressing position by locking the clamping lever 90. In a variant not shown in the figures, the applicator arm 82 can also be resiliently preloaded about its pivot axis 84 in the direction of the hose support 64, e.g., by means of a tension spring arranged for actuation between the applicator arm 82 and a lower part of the applicator carriage 72.

[0080] It will be apparent to those skilled in the art that these measures allow the applicator wheel 70 to be reliably held in engagement with the profile 20 of a hose 10 resting on the hose support 64. Hoses 10 with different diameters and shapes (e.g., substantially cylindrical or conical) can be processed, ie, provided with an electrically conductive thread 30.

[0081] Furthermore, how best to Fig. 10 , 11 and 14 As can be seen, the applicator arm 82 has a head part 92 made of an aluminum profile section, to which further components or assemblies of the applicator 68 are mounted, as described below. These components and assemblies are, in detail, a feed device 94 for the electrically conductive thread 30, a feed device 96 for the adhesive tape 40, a guide roller arrangement 98 with a pair of guide rollers 100, 102 for combining the electrically conductive thread 30 with the adhesive tape 40 before it is passed on to the applicator wheel 70, and a bearing and drive arrangement 104 for the applicator wheel 70.

[0082] According to the Fig. 10 , 11 and 14First, the guide roller assembly 98 is mounted by means of a bearing profile section 106 on top of the head part 92 of the applicator arm 82, so that the guide rollers 100, 102 are located above the applicator wheel 70 in a position aligned with the applicator wheel 70, as clearly shown in the Fig. 12 and 13 can be seen. The guide rollers 100, 102 are mounted on the bearing profile section 106 in a suitable manner.

[0083] On the side of the head part 92 and the bearing profile section 106 facing away from the pivot axis 84, a roll holder 108 of the feed device 96 is also mounted, at the free end of which a roll of adhesive tape 110 is rotatably mounted, also in a cantilevered manner. According to the Fig. 12 and 13 the adhesive tape roll 110, which is arranged with its axis of rotation above the guide roller arrangement 98, is also in alignment with the guide rollers 100, 102.

[0084] Furthermore, a spool holder 112 of the feed device 94 is mounted on top of the bearing profile section 106. In the illustrated embodiment, this spool holder supports four spools 114 with electrically conductive threads 30, which are rotatably mounted on parallel axle pins (not shown). At the end of the spool holder 112 facing away from the adhesive tape roll 110, a mounting bracket 116 is attached for one end of a hose 118, the other end of which is laterally attached to the bearing profile section 106 by means of a bracket 120. This bracket 120 also holds a tube 122 for feeding, or more precisely, guiding, the electrically conductive threads 30 to the guide roller assembly 98.

[0085] In this respect, it can be seen that the adhesive tape 40 can be unwound from the adhesive tape roll 110 of the feed device 96 and fed to the guide roller assembly 98. At the same time, electrically conductive threads 30 can be unwound from the spools 114, collected via the hose 118, and guided through the tube 122 to the guide roller assembly 98, where the electrically conductive threads 30 are combined with the adhesive tape 40.

[0086] Below the head part 92 of the applicator arm 82, a bearing block 124 of the bearing and drive arrangement 104 for the applicator wheel 70 is also mounted. In the illustrated embodiment, the bearing block 124 is formed in two parts, with a Fig. 13 left part, in which a drive shaft 126 for the applicator wheel 70 is rotatably mounted via two roller bearings, and a Fig. 13right part, on which an axle pin 128 is mounted for supporting the applicator wheel 70 by means of a wheel-side roller bearing. On the Fig. 12 and 13 Furthermore, a preferably electric rotary drive 132 is flanged to the left side of the bearing block 124 via a mounting flange 130, which is in driving connection with the applicator wheel 70 via the drive shaft 126.

[0087] Further details on the applicator wheel 70 are finally Fig. 10 and 12 to 14 Accordingly, the applicator wheel 70 has between two hub sections 134, 136 a plurality of - in the illustrated embodiment five (see Fig. 14 ) - evenly distributed over the circumference of the axle pins 138. The axle pins 138 each support a hollow cylindrical sleeve 140 as a pressing body for the electrically conductive thread 30 in a rotatable manner. Fig. 13It can also be seen that the hub section 134 of the applicator wheel 70 on the left in this figure is connected in a rotationally fixed manner to the drive shaft 126 in the manner of a coupling, while the hub section 136 of the applicator wheel 70 on the right in this figure accommodates the roller bearing, which cooperates with the axle pin 128 in the bearing block 124 to rotatably support the applicator wheel 70.

[0088] As in particular the Fig. 10 and 14As shown, the adhesive tape 40 combined with the electrically conductive threads 30 is guided from the guide roller arrangement 98 through a slot-like recess 142 in the head part 92 of the applicator arm 82 and in the bearing block 124 mounted thereon to the applicator wheel 70, via which the electrically conductive threads 30 are applied and secured under the adhesive tape 40 on the outer side 18 of the hose 10. The applicator wheel 70, whose sleeves 140 engage positively with the profile 20 of the hose 10, rolls on the hose 10.

[0089] It is evident that by driving the applicator wheel 70 by means of the rotary drive 132 not only the electrically contacting application and fastening of the electrically conductive threads 30 to the hose 10 takes place, but also the feed movement between the applicator 68 and the hose 10 lying on the hose support 64 is generated, in which the applicator carriage 72 moves as shown in the Fig. 7 to 9 shown moved over the hose support 64 fixed to the frame 56. At the end, the hose 10, whose electrically conductive path 28 is contacted or short-circuited via the applied electrically conductive threads 30, can be removed from the hose support 64 by the device 54, before the further assembly of the hose 10 takes place by possibly further cutting the hose 10 to length and attaching the hose receiving pieces 44, 46.

[0090] A flexible hose, in particular a vacuum cleaner hose, has a wall which, with an inner side, defines a cavity for conveying media and has a profile on at least one outer side which, when viewed in section along a longitudinal axis of the hose, has elevations and depressions. On the outer side of the wall, at least one electrically conductive track is provided which runs around the wall and is in electrical contact with at least one electrically conductive thread which electrically connects opposite ends of the hose. The electrically conductive thread is attached to the outer side of the wall, running essentially along the longitudinal axis of the hose and transversely to the electrically conductive track, whereby the hose has improved suitability for recycling when a relatively small amount of electrically conductive materials is used.Furthermore, a method for producing such a hose and a device which can be used for this purpose are proposed. LIST OF REFERENCE SYMBOLS

[0091] 10 Hose 12 Wall 14 Inside 16 Cavity 18 Outside 20 Profiling 22 Longitudinal axis 24 Raised portion 26 Recess 28 Electrically conductive path 30 Electrically conductive thread 32 End 34 End 36 Profile 38 Hot melt adhesive 40 Adhesive tape 42 Braiding 44 Hose receptacle 46 Hose receptacle 48 Internal thread section 49 End 50 Receptacle section 52 Electrically conductive adhesive 53 End 54 Device 56 Frame 58 Longitudinal profile 60 Cross profile 62 Holding profile 64 Hose support 66 Fastening tab 68 Applicator 70 Applicator wheel 72 Applicator carriage 74 Double arrow (axial movement) 76 Guide groove 78 Profile glider 80 Cross member 82Applicator arm 84Pivot axis 86Double arrow (pivoting movement) 88Joint 90Clamping lever 92Head part 94Feed device 96Feed device 98Guide roller assembly 100Guide roller 102Guide roller 104Bearing and drive assembly 106Bearing profile section 108Roll holder 110Adhesive tape roll 112Spool holder 114Spool 116Mounting bracket 118Hose 120Console 122Tube 124Bearing block126Drive shaft 128Axle pin 130Mounting flange 132Rotary drive 134Hub section 136Hub section 138Axle pin 140Sleeve 142Slot-like recess

Claims

1. Flexible hose (10), particularly vacuum cleaner hose, with a wall (12) which by an inner side (14) delimits a cavity (16) for the conveying of media and has at least at an outer side (18) a profiling (20) which as seen in section along a longitudinal axis (22) of the hose (10) has a wave shape with elevations (24) and depressions (26), wherein provided at the outer side (18) of the wall (12) is at least one electrically conductive track (28) which extends around the wall (12) and is in electrical contact with at least one electrically conductive thread (30) electrically connecting mutually remote ends (32, 34) of the hose (10), characterized in that the electrically conductive thread (30) extending substantially along the longitudinal axis (22) of the hose (10) and transversely to the electrically conductive track (28) is secured to the outer side (18) of the wall (12).

2. Flexible hose (10) according to claim 1, characterized in that the electrically conductive thread (30) is secured to the outer side (18) of the wall (12) by an adhesive strip (40).

3. Flexible hose (10) according to claim 2, characterized in that the adhesive strip (40) covers the electrically conductive thread (30) to both sides as seen in circumferential direction of the hose (10).

4. Flexible hose (10) according to any one of the preceding claims, characterized in that the electrically conductive thread or the adhesive strip (40) covering the electrically conductive thread (30) is surrounded at the outer side (18) of the wall (12) by a braiding (42) of the hose (10), and / or that the electrically conductive track (28) on the outer side (18) of the wall (12) is formed near to or at the elevations (24) of the profiling (20), and / or that the hose (10) is provided at one or both of the mutually remote ends (32, 34) with a hose mounting member (44, 46) of an electrically conductive material.

5. Flexible hose (10) according to claim 4, characterized in that the profiling (20) of the hose (10) at the outer side is helical and the end (32) of the hose (10) is screwed by the helical profiling (20) into an associated internally threaded section (48) of the hose mounting member (44), wherein the electrically conductive thread (30) is clamped between the profiling (20) and the internally threaded section (48) with formation of an electrical contact, and / or that the end (34) of the hose (10) is plugged into an associated receiving section (50) of the hose mounting member (46) and glued to the hose mounting member (46) by an electrically conductive adhesive (52), into which the electrically conductive thread (30) extends with formation of an electrical contact.

6. Flexible hose (10) according to any one of the preceding claims, characterized in that the wall (12) of the hose (10) is formed from a helically wound profile (36), wherein adjacent windings of the profile (36) are media-tightly connected together.

7. Flexible hose (10) according to claim 6, characterized in that the adjacent windings of the profile (36) are media-tightly connected together by a hot-melt adhesive (38).

8. Method of producing a flexible hose (10) according to any one of the preceding claims, characterized by the following method steps: a) forming a basic hose having a wall (12) which by an inner side (14) delimits a cavity (16) about a longitudinal axis (22) and has at least at an outer side (18) a profiling (20) which as seen in section has a wave shape with elevations (24) and depressions (26), wherein the wall (12) is formed from an electrically conductive material or at least one electrically conductive track (28) is formed at the outer side (18) of the wall (12) so that the electrically conductive track (28) extends around the wall (12), b) applying at least one electrically conductive thread (30) to the outer side (18) of the wall (12) so that the electrically conductive thread (30) extends substantially along the longitudinal axis (22) and transversely to the electrically conductive track (28) and c) securing the electrically conductive thread (30) to the outer side (18) of the wall (12) so that the electrically conductive thread (30) electrically contacts the electrically conductive track (28).

9. Method of producing a flexible hose (10) according to claim 8, characterized in that in step a) of forming the basic hose initially a profile (36) is extruded from an electrically conductive plastics material or co-extruded from two plastics materials of different electrical conductivity so that the profile (36) comprises at least one electrically conductive track (28), whereupon the profile (36) is helically wound to form the wall (12) of the basic hose, wherein adjacent windings of the profile (36) are media-tightly connected together.

10. Method of producing a flexible hose (10) according to claim 9, characterized in that the adjacent windings of the profile (36) are media-tightly connected together by a hot-melt adhesive (38).

11. Method of producing a flexible hose (10) according to any one of claims 8 to 10, characterized in that the steps b) of applying and c) of securing the electrically conductive thread (30) to the outer side (18) of the wall (12) are performed at the same time, and / or that after the step c) of securing the electrically conductive thread (30) to the outer side (18) of the wall (12) a hose mounting member (44, 46) of an electrically conductive material, which electrically contacts the electrically conductive thread (30), is attached to one or both of the mutually remote ends (32, 34) of the hose (10) cut to length.

12. Device (54) for applying an electrically conductive thread (30) to an outer side (18) of a flexible hose (10) according to any one of claims 1 to 7, wherein the outer side (18) of the hose (10) has a profiling (20) which as seen in section along a longitudinal axis (22) of the hose (10) has a wave shape with elevations (24) and depressions (26), characterized by an applicator (68) for the electrically conductive thread (30), the applicator having a rotatable applicator wheel (70) which is similar to a stock wheel or cell wheel and at the outer circumference of which the electrically conductive thread (30) can be fed, the applicator wheel being adapted to enter into interlocking engagement with the profiling (20) of the hose (10) placeable in a hose support (64) so that when the applicator wheel (70) is rotating a relative advance movement between hose (10) and applicator (68) takes place, in which the applicator wheel (70) applies the electrically conductive thread (30) to the profiling (20) of the hose (10) along the longitudinal axis (22) of the hose (10) to follow the elevations (24) and depressions (26).

13. Device (54) according to claim 12, characterized in that the applicator (68) comprises an applicator arm (82) on which the applicator wheel (70) is rotatably mounted and which is pivotable with respect to the hose support (64) about a selectively fixable pivot axis (84).

14. Device (54) according to claim 13, characterized in that the applicator arm (82) together with the applicator wheel (70) and the pivot axis (84) thereof is so arranged with respect to the hose support (64) that a torque about the pivot axis (84) arises in the direction of the hose support (64) and / or that the applicator arm (82) is resiliently biased about its pivot axis (84) in the direction of the hose support (64).

15. Device (54) according to any one of claims 12 to 14, characterized in that the device (54) comprises a frame (56) on which the hose support (64) is mounted in stationary position, wherein the applicator (68) comprises an applicator carriage (72) which carries the applicator wheel (70) and is guided at the frame (56) to be displaceable along the hose support (64), and / or that the applicator (68) comprises a feed device (94) for the electrically conductive thread (30) and a feed device (96) for an adhesive strip (40), wherein the electrically conductive thread (30) and the adhesive strip (40) can be fed from the feed devices (94, 96) to a pair of guide rollers (100, 102) which are adapted to combine the thread (30) and adhesive strip (40) before being passed on to the applicator wheel (70), and / or that the applicator wheel (70) has between two hub sections (134, 136) a plurality of axle pins (138) which are distributed uniformly over the circumference and which each rotatably mount a respective hollow-cylindrical sleeve (140) as pressing body for the electrically conductive thread (30), and / or that the applicator wheel (70) is drivably connected with a rotary drive (132).