powder jet device

Abstract

Powder jet device for cleaning tooth surfaces by applying a powder-gas mixture, comprising a stationary unit (20) with a connection area for a mixing chamber (32) for producing the powder-gas mixture, a handpiece (100) with a nozzle device (102) for blasting the powder-gas mixture onto a tooth surface and a connecting unit (40) for connecting the handpiece (100) to the stationary unit (20), wherein the connecting unit (40) has at least one connecting guide (42) between the stationary unit (20) and the handpiece (100), and wherein a hose section (92) which can be shut off by elastic deformation is arranged in a powder-gas line (44) between the mixing chamber (32) and the nozzle device (102), characterized by that the connecting unit (40) is detachably connected to the stationary unit (20) and that the lockable hose section (92) is arranged in the detachable connection unit (40), wherein the connecting unit (40) has a housing (52) connected to the connecting guide (42), in which the lockable hose section (92) and a pinch element (94) are arranged as a pinch valve and that the connecting unit (40) has a first coupling area (64) for coupling to a corresponding second coupling area (34) of the stationary unit (20).

Description

[0001] The invention relates to a powder jet device for cleaning tooth surfaces by applying a powder-gas mixture and a connecting unit for a powder jet device.

[0002] Powder jet devices (dental abrasive jet devices) for cleaning, in particular for powder jetting or polishing, tooth surfaces using an abrasive dental cleaning powder are known in the prior art. For cleaning tooth surfaces, the dental cleaning powder is jetted onto the tooth surface using a gaseous carrier medium, usually air. Additionally, a liquid medium, usually water, is typically supplied to the patient's mouth via a separate line. The liquid serves to prevent uncontrolled spraying of the powder during dental treatment and to rinse away the removed dirt particles, including any powder particles remaining in the patient's mouth.

[0003] A powder jet device of the type mentioned above is described, for example, in EP 0 097 288 B1. This powder jet device comprises a box-shaped base station (stationary unit) with a housing containing a powder container that holds dental powder. Compressed air is introduced to agitate the dental powder, which is then directed through an outlet opening into a hose inside the base station housing. A pinch valve in the hose interrupts the flow of the powder-gas mixture. The pinch valve is operated by compressed air, which is supplied from a compressed air line located upstream of the powder container. A handpiece is connected to the base station via a connecting hose containing two separate lines for the powder-gas mixture and water.

[0004] US Patent 2,696,049 A describes a medical device for removing tooth material using an abrasive jet. A magnet vibrates a powder chamber, ultimately generating the abrasive powder mixture.

[0005] US 2004 / 0197731A1 concerns a powder-gas jet device that uses pressurized helium.

[0006] Another powder jet device is described in EP 1 972 295 B1. This powder jet device comprises a base station (stationary unit) with a receiving area for an interchangeable powder container, which has a swirl chamber for producing a powder-gas mixture. A handpiece is connected to the base station via a connecting cable. The base station contains a control panel for setting operating parameters, such as the strength of the powder jet or a water jet.

[0007] For optimal handling of a powder jet device, it is desirable that the treatment can be started and stopped with minimal delay. Known powder jet devices use a pinch valve to interrupt the powder-gas flow, as described, for example, in EP 0 097 288. This valve is located in the stationary unit, specifically between the powder container and the connection of the line leading to the handpiece. The pinch valve can be actuated, for example, by a solenoid valve or a pneumatic cylinder. With a pinch valve, an elastic section of tubing is pinched and thus sealed, blocking the flow of the powder-gas mixture. Compared to other valve types, the pinch valve has the advantage of avoiding dead zones, which are detrimental in a powder flow.

[0008] A disadvantage of pinch valves, however, is that the abrasive effect of the dental powder and the repeated mechanical pinching of the tubing cause wear, which can lead to valve failure. This then results in powder leaking into the housing of the stationary unit.

[0009] It was therefore proposed to dispense with pinch valves in the powder line (the line for the powder-gas mixture). Instead, it was suggested that the supply of compressed air to the powder chamber be interrupted at the end of the dental treatment. This can be done with conventional shut-off valves. However, a disadvantage of this method is that the treatment is not stopped immediately, as the pressure in the powder chamber must first be released, which can take several seconds. The same applies to the beginning of a treatment, where pressure must first be built up in the powder chamber using this approach.

[0010] The invention is based on the objective of providing a powder jet device and components of a powder jet device, such that the powder jet device is particularly reliable and durable while being as comfortable to use as possible.

[0011] The problem is solved according to the invention by a powder jet device with the features of claim 1 and by a connecting unit with the features of claim 11. Preferred embodiments of the invention are specified and further explained in the dependent claims and the following description, in particular in connection with the accompanying figures.

[0012] The powder jet device according to the invention for cleaning tooth surfaces by applying a powder-gas mixture comprises a stationary unit (base station) with a connection area for a mixing chamber for producing the powder-gas mixture, a handpiece with a nozzle assembly for blasting the powder-gas mixture onto a tooth surface, and a connecting unit for connecting the handpiece to the stationary unit. The connecting unit has at least one connecting guide between the stationary unit and the handpiece. A hose section, which can be shut off by elastic deformation, is arranged in a powder-gas line between the mixing chamber and the nozzle assembly. The invention is characterized in that the connecting unit is detachably connected to the stationary unit and that the shut-off hose section is arranged in the detachable connecting unit.

[0013] The connection unit according to the invention for a powder jet device for cleaning tooth surfaces by applying a powder-gas mixture is designed to connect a handpiece of the powder jet device to a stationary unit (base station) of the powder jet device and has a connecting guide for arrangement between the stationary unit and the handpiece. The connection unit is provided to have a connection area, or coupling area, for detachable connection to the stationary unit and to have a powder-gas line for conveying a powder-gas mixture with a hose section (line section) that can be shut off by elastic deformation.

[0014] A primary concept of the invention is to integrate a pinch valve, at least partially, into the connecting unit. A pinch valve comprises, as one component, a lockable (closable), elastic hose section (pipe section). According to the invention, this component of the pinch valve is not located in the stationary unit, but rather in the connecting unit between the stationary unit and the handpiece. A further component of a pinch valve is a means or device for compressing or pinching the hose section, particularly in a controlled manner. This device is preferably also located in the connecting unit, but can, in principle, also be located in the stationary unit.

[0015] The connecting unit is designed to be detachably (separable, removable) connected to the stationary unit. This ensures that if the pinch valve, particularly the lockable hose section, malfunctions, a costly repair of the stationary unit is unnecessary; only the connecting unit needs to be replaced. This significantly speeds up and reduces the cost of repairs. Furthermore, positioning the lockable hose section outside the stationary unit prevents powder from entering the unit's interior, which typically houses electronic components, especially control elements, in the event of a leaking hose section.Finally, a user can more easily detect the defect, since if the pinch valve (the lockable hose section) leaks, powder will be visibly escaping from the connection unit and entering the environment.

[0016] For cost-effective replacement of the connection unit, it is preferably detachably (separably) connected not only to the stationary unit but also to the handpiece. The connection unit, including the lockable hose section of the pinch valve, can therefore be replaced individually while retaining both the stationary unit and the handpiece.

[0017] The connecting unit, which is particularly flexible (bendable) and can be, for example, a connecting hose, connecting cable, or other guide for a flexible line, preferably includes a first line (supply line) for the powder-gas mixture (powder-gas line, powder line) and a second line (supply line) for a liquid (liquid line). The two lines are connected to separate nozzles of a nozzle assembly on the handpiece, so that the liquid can be directed onto the tooth surface separately from the powder-gas stream. The liquid stream serves, in a generally known manner, to remove the powder after it impacts the tooth surface and / or to control the spraying of the powder during dental treatment. The nozzle for the liquid jet can surround the powder-gas nozzle in a ring-like configuration for this purpose.

[0018] According to the invention, the connecting unit comprises a housing body (housing) connected to the connecting guide to accommodate the lockable hose section. In contrast to the connecting guide, the housing body, which is rigid or dimensionally stable, serves to accommodate the elastic, lockable hose section and optionally further components of the pinch valve, for example, a pressure chamber for a control fluid, in particular a control gas, and, according to the invention, a pinch element for compressing the lockable hose section.A key aspect of the invention can therefore also be seen in the fact that the connecting unit serving to connect the handpiece to the stationary unit comprises, in addition to a flexible (bendable) connecting element (connecting cable, connecting hose), a housing body suitable for holding and receiving components of a pinch valve, in particular a lockable, elastic hose section of a powder-gas line. For this purpose, the housing body comprises a rigid housing. The elastic hose section is held in the housing body by means of at least one rigid retaining element, in particular a rigid line section. The elastic, lockable hose section can also be clamped between retaining elements (rigid line sections).Preferably, the lockable or compressible elastic hose section of the pinch valve is formed integrally with a line section of the powder-gas line in the connecting guide leading to the handpiece.

[0019] According to the invention, the connecting unit is provided for the detachable connection of the connecting unit to the stationary unit by having a first coupling area (connection area, connection area) for coupling (connecting) to a corresponding second coupling area (connection area, connection area) of the stationary unit. The first coupling area is provided on the housing body of the connecting unit, so that the housing body of the connecting unit can be directly connected or coupled to the housing of the stationary unit. The connecting unit thus comprises a housing body with a coupling area for coupling to the stationary unit or the housing of the stationary unit and a connecting guide with a powder-gas line and preferably additionally a liquid line, which is connected to the handpiece.The coupling areas may, if necessary, be formed on independent coupling parts of the stationary unit and / or the connecting unit.

[0020] The pinch valve is preferably actuated by means of a control fluid, in particular a pressurized gas, preferably compressed air. The control fluid or compressed air is preferably routed from the stationary unit to the connecting unit. For this purpose, a coupling for a control element for controlling the pinch valve, in particular a line coupling for a control fluid line, preferably for a compressed air line, is preferably formed between the connecting unit and the stationary unit. The line coupling preferably comprises corresponding coupling elements on the first coupling area or coupling part (of the connecting unit) and the second coupling area or coupling part (of the stationary unit). The connecting unit preferably comprises a pressurized gas line, in particular a compressed air line, which can also be referred to as a control fluid line.A control fluid (compressed air) is supplied via the compressed gas line to the pinch valve in the connecting unit, which serves as an on / off command or open / close command for the pinch valve. Alternatively, the pinch valve can also be actuated electromechanically.

[0021] Furthermore, it is preferred that a line coupling for a fluid line is formed between the connecting unit and the stationary unit in order to direct the fluid from the stationary unit to the connecting unit and via this unit to the handpiece.

[0022] It is also preferred according to the invention that a line coupling for a powder-gas line is formed between the connecting unit and the stationary unit. In an advantageous embodiment, the mixing chamber is arranged on the stationary unit or forms part of the stationary unit. The powder-gas mixture leaves the mixing chamber via a powder-gas line and reaches the detachable connecting unit via the line coupling, which contains the lockable line or hose section of the pinch valve.

[0023] The connection zone (coupling zone) between the stationary unit and the connecting unit therefore preferably contains a liquid connection (for cleaning treatment) and / or a powder-gas connection (for cleaning treatment) and / or an air connection (compressed air connection) for actuating (activating) the pinch valve.

[0024] The mixing chamber can also form a unit together with the lockable hose section (and preferably the handpiece), which is interchangeably coupled to the stationary unit. In this case, where the mixing chamber can be considered part of the detachable connection unit, a line coupling for a compressed air line to the mixing chamber is formed between the connection unit and the stationary unit. The compressed air line supplies compressed air to the mixing chamber. The mixing chamber can be housed in the body of the connection unit, integrated into the housing, or designed as a separate element of the connection unit.

[0025] The connecting unit preferably comprises a control chamber for a pressurized control fluid and / or a pinch or control element for shutting off the hose section. The control chamber (fluid chamber, cavity, pressure chamber) or the control element is, in particular, arranged in the housing of the connecting unit. The control fluid is, in particular, compressed air. The shut-off hose section, which forms a shut-off element of the pinch valve, can be pinched or compressed and thus sealed by pressurizing it with the control fluid. Alternatively, the pinching or sealing (shutting off) of the hose section can be effected by a pinch or control element, in particular a plunger. This plunger can, in turn, be actuated by means of a control fluid, in particular compressed air.

[0026] In a preferred embodiment of the invention, the stationary unit comprises a control device, in particular a controllable valve, especially a solenoid valve, for controlling the control fluid, in particular compressed air. The stationary unit thus includes a device for supplying a compressed gas, in particular compressed air, for activating the shut-off of the hose section, which can be considered a part (component) of the pinch valve. This device (activation device) in the stationary unit can, in particular, provide an on / off command, especially by the presence or absence of compressed air (supply or non-supply of compressed air at a pinch element or in a pressure chamber of the pinch valve).Compressed air can be transferred from the stationary unit to the connecting unit via a line coupling (compressed gas coupling, control coupling). The connecting unit contains the lockable, flexible hose section and, if applicable, the pinch / pressure element for pinching (compressing, closing) the hose section and / or a pressure chamber. The pinch function, or activation of the pinch valve, is thus divided into two subsystems: The activation command is provided in the stationary unit, for example, by a valve, such as by supplying compressed air. The closing of the hose section of the pinch valve takes place in the detachable connecting unit, for example, by a cylinder or a pressure / pinch element.

[0027] The connecting unit preferably comprises a locking device / mechanism for positive and / or force-fit connection or mechanical locking with the stationary unit. The locking device can, for example, have finger- or hook-shaped locking elements. For example, the connecting unit can be latched to the stationary unit, in particular such that the connection can only be released by actuating a release device.

[0028] Preferably, a release device is provided for the targeted unlocking of the connection between the connecting unit and the stationary unit. The connecting unit and the stationary unit are preferably coupled / connected to each other in such a way that the coupling / connection can be released (exclusively) by actuating the release device. This ensures that the connecting unit and the stationary unit cannot be separated from each other without actuating the release device. This establishes a secure connection.

[0029] The invention is further described below with reference to preferred embodiments, which are illustrated in the accompanying schematic figures. The figures show: Fig. 1: an exemplary embodiment of a powder jet device according to the invention; Fig. 2: an exemplary embodiment of a connecting unit according to the invention in a perspective view; Fig. 3: the connecting unit according to Fig. 2 in a top view; Fig. 4: the connecting unit according to Fig. 2 in a sectional view; Fig. 5: the connecting unit according to Fig. 4 together with a coupling part of a stationary unit in a decoupled state; Fig. 6: the order according to Fig. 5 in a coupled state; Fig. 7: a perspective view of the unit according to Fig. 6 including a handpiece; and Fig. 8: a schematic representation of components of a powder jet device according to the invention.

[0030] Identical or similarly effective elements are marked with the same reference symbols in all figures.

[0031] Fig. Figure 1 shows the basic structure of a powder jet device 10 according to the invention. The powder jet device 10 comprises a stationary unit 20, which can also be referred to as the base unit. The stationary unit 20 comprises a housing 21 with a base area 22 for placing it on a surface, for example, a table. Control elements for controlling the operation of the powder jet device 10, in particular electronic components, are housed in the housing 21. The stationary unit 20 has means for supplying compressed gas, in particular compressed air, to a mixing chamber 32, in which a powder-gas mixture or a powder-air mixture is produced using the compressed gas or compressed air. Furthermore, the stationary unit 20 can have an on / off switch 23, as shown in the figure. Fig. Figure 1 shows the stationary unit 20. Finally, the stationary unit 20 may have a control panel or input device 26 for entering commands and / or a display device 28 for displaying status information. The stationary unit 20 has a connection area for connecting a powder container 30, which contains dental powder for cleaning tooth surfaces. The powder container 30, which can be considered part of the stationary unit 20 or a separate element, comprises a mixing chamber 32, in particular within a housing of the powder container 30. In the mixing chamber 32, the powder (dental powder) is swirled with the compressed air, and a powder-gas mixture or powder-air mixture is provided at an outlet opening of the mixing chamber 32.A powder-gas line 44 leads from the mixing chamber 32 via a connecting unit 40, which is described in more detail below, to a handpiece 100, which is positioned in the mouth of a patient during application.

[0032] The connecting unit 40, which can also be referred to as a hose unit or cable unit, comprises, in a known manner, a flexible connecting guide 42, for example, a (flexible) connecting cable or a (flexible) connecting hose, between the stationary unit 20 and the handpiece 100. The powder-gas line 44 (or a section thereof) and a liquid line 46, which transports a liquid, usually water, to the handpiece 100, run within the connecting guide 42. The handpiece 100 includes a nozzle assembly 102, which has separate nozzles for the powder-gas mixture on the one hand and the liquid on the other. In addition to the flexible connecting guide 42, the connecting unit 40, which connects the stationary unit 20 to the handpiece 100, includes a housing body 50 with a housing 52, for example, cylindrical. In the illustrated embodiment, the housing body 50 is...The housing 52 is coupled to (connected to) the stationary unit 20. For this purpose, the housing body 50 or the housing 52 comprises a first coupling area or connection area 64. The stationary unit 20 has a second coupling area or connection area 34, which can be coupled or connected to the first coupling area 64. The second coupling area 34 is formed by a coupling part 36, which is attached to the housing 21 of the stationary unit 20. The housing 52 of the connecting unit 40 can be locked to the housing 21 of the stationary unit by means of locking elements 82, in particular such that a release device 38 must be actuated to unlock it.

[0033] At least part of a pinch valve 90 is arranged in the housing 52 or housing body 50 of the connecting unit 40. In other words, the pinch valve 90 is integrated, or at least partially integrated, into the connecting unit 40. The pinch valve 90 comprises a lockable, elastic hose section 92 of the powder-gas line 44, which is arranged in the connecting unit 40, in particular in the housing body 50 or housing 52.

[0034] Furthermore, the pinch valve 90 comprises a pinch element or control element 94, which can also be referred to as a control pin, for pinching (compressing / shutting off) the hose section 92. The pinch element 94 is preferably also arranged in the housing 52 or at least projects into it.

[0035] The pinch element 94 is actuated by means of a pressurized gas, in particular compressed air. The compressed air is supplied in the stationary unit 20 and transferred to the connecting unit 40 via a coupling described in more detail below.

[0036] The connecting unit 40 with connecting guide 42 and housing body 50 is described below with reference to the Fig. 2, Fig. 3 to Fig. 4 described in more detail. Fig. 5 and Fig. Figure 6 shows the coupling of the connecting unit 40 with the stationary unit 20, in particular with the coupling part 36 of the stationary unit 20. The housing body 50, which is particularly cylindrical, has an end face on which the first coupling area 64 is formed. The first coupling area 64 comprises a first coupling element 69 for forming a line coupling 68 for the powder-gas line 44. Furthermore, the first coupling area 64 comprises a third coupling element 73 for forming a line coupling 72 for the liquid line 46. In addition, the first coupling area 64 comprises a fifth coupling part 77 for forming a control coupling 76, for example, a line coupling, for actuating the pinch valve 90 or for actuating or actuating the pinch element 94.In the illustrated embodiment of the invention, the control coupling 76 is also a line coupling, namely for transferring compressed gas, in particular compressed air, from the stationary unit 20 to the connecting unit 40.

[0037] The second connection area 34, or coupling part 36, of the stationary unit 20 comprises a second coupling element 70 for coupling with the first coupling element 69, a fourth coupling element 74 for coupling with the third coupling element 73, and a sixth coupling element 78 for coupling with the fifth coupling element 77. The first and second coupling elements 69 and 70 together form the line coupling 68 for the powder-gas line 44. The third coupling element 73 and the fourth coupling element 74 form the line coupling 72 for the liquid line 46. The fifth and sixth coupling elements 77 and 78 form the control coupling 76. The control coupling 76 is preferably a line coupling for compressed air for actuating the pinch element 94 of the pinch valve 90.

[0038] The pinch valve 90 in the connecting unit 40 has a compressed air connection 97 to a control chamber 96, which is connected via the control coupling 76 to a control fluid line (compressed air line) 48 in the stationary unit 20. A first movable element 98 is pressed into a release position by a first (outer) spring, in which the hose section 92 is open. By applying pressure against the spring force, the first movable element 98 is pressed into a pinch or closed position, in which the hose section 92 is closed. A second movable element 99, also spring-loaded, within the first movable element 98 prevents excessive pressure from being exerted on the hose section 92.

[0039] As especially in the Fig. 2 and Fig. As can be seen in Figure 7, the housing 52 of the connecting unit 40 includes a holding area 54 for the handpiece 100. The holding area 54 is formed as a recess in the housing 52 and preferably holds the handpiece 100 in a form-fitting manner.

[0040] Fig.Figure 8 abstractly illustrates the interaction of stationary unit 20, connecting unit 40, and handpiece 100. The connecting unit 40, which can be disconnected from stationary unit 20, is supplied with a powder-gas mixture via the powder-gas line 44 and with a liquid via the liquid line 46. The powder-gas mixture and the liquid are used for patient treatment or tooth cleaning and are directed to the handpiece 100. In addition, the disconnectable connecting unit 40 is supplied with compressed gas (compressed air) via the control fluid line 48, which leads to the pinch valve 90 and serves to actuate / activate it. The couplings 68, 72, and 76, which have already been described, are located at the interface between stationary unit 20 and connecting unit 40.

Claims

[1] Powder jet device for cleaning tooth surfaces by applying a powder-gas mixture, comprising a stationary unit (20) with a connection area for a mixing chamber (32) for producing the powder-gas mixture, a handpiece (100) with a nozzle device (102) for blasting the powder-gas mixture onto a tooth surface and a connecting unit (40) for connecting the handpiece (100) to the stationary unit (20), wherein the connecting unit (40) has at least one connecting guide (42) between the stationary unit (20) and the handpiece (100), and wherein a hose section (92) which can be shut off by elastic deformation is arranged in a powder-gas line (44) between the mixing chamber (32) and the nozzle device (102), characterized by , that the connecting unit (40) is detachably connected to the stationary unit (20) and that the lockable hose section (92) is arranged in the detachable connection unit (40), wherein the connecting unit (40) has a housing (52) connected to the connecting guide (42), in which the lockable hose section (92) and a pinch element (94) are arranged as a pinch valve and that the connecting unit (40) has a first coupling area (64) for coupling to a corresponding second coupling area (34) of the stationary unit (20). [2] Powder jet device according to one of claims 1 , characterized by , that a coupling (76) for a control fluid line (48) is formed between the connecting unit (40) and the stationary unit (20). [3] Powder jet device according to one of claims 1 or 2, characterized by , that a line coupling (72) for a liquid line (46) is formed between the connecting unit (40) and the stationary unit (20). [4] Powder jet device according to one of claims 1 to 3, characterized by , that a line coupling (68) for a powder gas line (44), or a line coupling for a compressed air line to the mixing chamber (32), is formed between the connecting unit (40) and the stationary unit (20). [5] Powder jet device according to any one of claims 1 to 4, characterized by , that the mixing chamber (32) together with the lockable hose section (92) forms a unit which is interchangeably coupled with the stationary unit (20). [6] Powder jet device according to any one of claims 1 to 5, characterized by , that the connecting unit (40) has a control chamber (96) for a pressurized control fluid and / or a control element (94) for shutting off the hose section (92). [7] Powder jet device according to any one of claims 1 to 6, characterized by, that the stationary unit (20) has a control device, in particular a controllable valve, in particular a solenoid valve, for controlling the control fluid. [8] Powder jet device according to any one of claims 1 to 7, characterized by , that a release device (38) is provided for the targeted release of the connection between the connecting unit (40) and the stationary unit (20). [9] Powder jet device according to any one of claims 1 to 8, characterized by , that the control element (94) is stored in the stationary unit (1) and engages in or on the connection unit (40) to shut off the hose section (92). [10] Powder jet device for cleaning tooth surfaces by applying a powder-gas mixture, comprising a stationary unit (20) with a connection area for a mixing chamber (32) for producing the powder-gas mixture, a handpiece (100) with a nozzle device (102) for blasting the powder-gas mixture onto a tooth surface and a connecting unit (40) for connecting the handpiece (100) to the stationary unit (20), wherein the connecting unit (40) has at least one connecting guide (42) between the stationary unit (20) and the handpiece (100), and wherein a hose section (92) which can be shut off by elastic deformation is arranged in a powder-gas line (44) between the mixing chamber (32) and the nozzle device (102), characterized by , that the connecting unit (40) is detachably connected to the stationary unit (20) and that means for regulating a liquid flow is arranged in the detachable connection unit (40), wherein the connection unit (40) has a housing (52) connected to the connection guide (42), in which the lockable hose section (92) and a pinch element (94) are arranged as a pinch valve and that the connecting unit (40) has a first coupling area (64) for coupling to a corresponding second coupling area (34) of the stationary unit (20), wherein the housing body of the connecting unit can be directly connected to the housing of the stationary unit. [11] Powder jet device according to claim 10, characterized by , that the means for regulating the fluid flow shall include at least one electric or pneumatic valve arranged in the detachable connecting unit (40). [12] Powder jet device according to claim 11, characterized by, that the pneumatic valve is controlled via a control pin which is stored in the stationary unit (1).

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