DE102014117603A1 - Hand tools, in particular impact wrenches - Google Patents

Abstract

It is a powered with compressed air hand tool (10) with rotating tool shaft (14) disclosed. The tool shaft (14) is coupled to a percussion mechanism for generating or exerting a periodic impact function acting in the radial direction on the tool shaft (14). The hand tool (10) comprises at least one actuating element (20) for activating the pneumatic drive for the tool shaft (14). Between a compressed air connection (22) of the hand tool (10) and the compressed air drive of the tool shaft (14) at least one pilot operated 5/3-way valve (26) for activation and for controlling the functions of the hand tool (10) is arranged with the at least one Actuator (20) is operatively connected and can be controlled by this or this.

Description

The present invention relates to a hand tool, in particular in the form of a pneumatically driven impact wrench with the features of independent claim 1.

Generic impact wrench with rotating intervention tools are known in different embodiments with mechanical, electric or pneumatic drives. Such impact wrenches generally serve to tighten or loosen screw connections, i. of screws and / or nuts, v.a. if high torques are required for the appropriate tightening and / or loosening operations.

Under an impact wrench is understood in the present context, a tool that combines a fast or slowly rotating tool shaft with an end fitting tool such as. A so-called hex socket or the like. With a percussion, which directed in the direction of rotation of the tool shaft and wielding a rotary motion superimposed beating float. In this way, such an impact wrench superimposed on a rotating release or tightening movement of a with the fitting tool such. the socket connected hexagonal screw head or a hexagon nut a striking rotary motion or beating pulses acting in tightening or loosening the screw head or on the threaded nut and thus makes it possible, a very tight-fitting screw with the application of a smaller Torque solve as this would be possible without simultaneous impact movement. The same applies to a tightening of such a screw in which by the simultaneous use of the percussion also a higher tightening torque can be achieved than in conventional screwdrivers without accompanying percussion.

Electrically operating devices have a tool shaft driven by an electric motor and a percussion device designed according to the intended use. The advantage of electric impact wrenches is in the permanent provision of small and medium torques at relatively compact device sizes and thus a certain amount of location independence, as to their operation usually only a connection to the local power grid or, if this is not directly possible to a generator provided for such a purpose must be produced. Due to the developments in the field of energy storage technologies, devices that are equipped with accumulators are also increasingly found, with their field of application mostly limited to the home user sector or semi-professional applications.

For higher requirements with regard to the duration of use and / or the torques to be overcome, as well as in professional use, normally air-operated or pneumatically operated impact wrenches are used. Such pneumatically operated impact wrench usually have a vane motor, which is rotated by compressed air in rotation and drives in this way the rotatably connected with the vane motor tool shaft. An internal percussion mechanism can, for example, have an energy store and suitable devices for introducing the impact pulses acting in the direction of rotation into the rotating tool shaft. As mentioned above, a variety of tool attachments can be arranged at the front end of the tool shaft, for example. Screw heads with hexagonal or polygonal, so-called. Screw nuts with which particular screw can be tightened or loosened, the tightening torque is usually very precisely adjustable. When loosening and tightening such screw is usually the impact function, are generated in the rapid impact sequences in the radial direction of the tool shaft, indispensable.

In the interests of ease of use and a reduction in the burden on the user, these impact wrenches should be as compact and lightweight as possible with high performance, to which the pneumatic drive delivers its magnitude due to the high power density possible. However, in conventional impact wrenches with their manual switches and valves, there are some restrictions which undesirably reduce power density, or require a corresponding increase in supply air pressure to maintain a desired power density.

Therefore, the primary object of the present invention is to improve the hand tool used to accomplish the abovementioned objects to the extent that the sources of error associated with its use are largely eliminated, the handling improved and the working speed increased. In addition, the asked with the invention available impact wrench with ease of use have the highest possible power density.

These stated objects of the invention are achieved with the subject matters of the independent claims. Features of advantageous developments of Invention will be apparent from the dependent claims.

To achieve the above-stated object, the present invention proposes a hand tool with a rotating tool shaft, which is coupled with a hammer mechanism for exercising and / or generating a periodic impact function acting in the radial direction on the tool shaft. The tool shaft of the hand tool is acted upon by compressed air, which ensures the desired rotation at a predeterminable rotational speed and / or with a definable torque. The compressed air usually acts on a turbine, which converts the pneumatic pressure and the pneumatic volume flow into a fast rotation of the tool shaft. At the front end of the tool shaft different tool attachments can be arranged, for example. Screw heads with external or internal hex, so-called. Screw nuts with which particular screw can be tightened or loosened. Other sockets with special fits can also be driven in rotation using the impact wrench.

The hand tool according to the invention requires an actuating element for presetting the various functions of the hand tool and / or for influencing various operating parameters. This actuator can basically and in a simple construction by an externally arranged on a tool housing or on a tool handle handle actuator for manual activation of the rotationally acting pneumatic drive for the tool shaft and / or the radially acting impact function and / or pre-selection of a direction of rotation of the tool shaft , However, this is by no means limiting, since the actuator can also be assigned more complex tasks. Thus, the actuator may also be part of a more complex control electronics or a microprocessor control that can provide depending on various other parameters such as. A torque detection for activation, shutdown or reverse rotation. In addition, at least parts of the functions of the hand tool according to the invention can be controlled remotely.

In this case, according to the present invention, at least one pilot-operated 5/3-way valve for activating and controlling the functions of the hand tool is arranged between a compressed air connection of the hand tool and the compressed air drive of the tool shaft. This multi-way valve is operatively connected to the at least one actuating element and controlled by this. Optionally, in the hand tool according to the invention, the 5/3-way valve may be formed by an electromagnetically pilot operated 5/3-way valve. This can be coupled in particular via electrical line connections to the at least one actuating element and thus be controlled by this. However, it is also possible to use feedforward control with piezoelectric actuators or an electromotive feedforward control which can be used e.g. with spindle drives can act on the pilot valves of the 5/3-way valve. Further variants of the precontrol are conceivable and included in the present invention.

The use of the electromagnetically, piezoelectrically or electromotively piloted 5/3-way valve has a particularly advantageous effect both on the air flow and on the construction of the hand tool according to the invention. For example, occur in a combination of 5/2-way valve used as a directional slide and an additional ball seat valve to interrupt the air or pneumatic flow unwanted throttling and resistance losses in the supply line, in the pressure switch and the directional slide, for example the throttle or resistance losses are greater, the more components are in the pneumatic flow or are part of the same. In order to reduce this loss of resistance, which can reduce the output pressure of the pneumatic volume flow by a third or more in the described configuration, it is provided in a first step, the combination of ball seat valve and 5/2-way valve in the hand tool according to the invention by a pilot-controlled 5/3-way valve to replace, which in particular can be dispensed with the installation of a throttling acting ball seat valve, so that fewer components in the supply line, ie are in the pneumatic volume flow; This not only simplifies the overall design of the impact wrench according to the invention, but also allows the optimization of the conduction and air flow for the pneumatic volume flow. A mechanical switching of the compressed air flow is now still fully possible, but this is limited to the pilot air, so that there are much more favorable conditions with respect to the air flow.

It is now particularly advantageous if the pilot control of the 5/3-way valve is formed by an electromagnetic, piezoelectric or electromotive pilot control, since further advantages can result with regard to the drive logic, the switch arrangement, the controllability and possibly remote controllability. The pilot control lines of the 5/3-way valve can each have electromagnetic and / or piezoelectric or electromotive controls. The actuator for the feedforward control can in a simple construction example. By at least one electric button, switch, a rocker switch, rocker switch, or similar be formed, optionally also several of these elements or switches or switching elements for different functionalities - here, for example, the direction of rotation reversal for the compressed air drive called - may be provided.

The at least one electrical actuator or switch is normally coupled via electrical leads to the 5/3-way valve which is biased magnetically or otherwise (e.g., piezoelectrically or electromotively); if it is actuated, then a circuit is closed, whereupon the respective magnet located in this circuit or the actuator or drive located in this circuit is actuated, which performs or triggers the desired switching operation. In this way, e.g. the directional slide for the compressed air no longer purely mechanical way, for example. By means of a hand-applied from the side by hand striking motion, are moved to the desired position; instead, the same effect can be triggered by means of a comparatively gentle pressure on an electrical actuator, which triggers the actual displacement of the directional slide via a pilot control. Similarly, these switching functions or at least parts of these switching functions can be taken over by a microprocessor control and / or a (partial) remote control.

This type of operation can bring additional benefits, since by a lateral or rotary impact movement, even if it is performed with little force, the hand tool is deflected or slightly twisted in the direction of the impact and therefore by the user by a corresponding countermovement or holding force must be stabilized again. Such a process requires additional expenditure of force and time and as a result reduces the reaction time required for the further processing of, for example, a wheel change, whereas the same process, e.g. triggered by an electromagnetic pilot control of the 5/3-way valve, the position of the directional slide changed without affecting the position of the hand tool itself noticeably.

Optionally, however, the at least one electrical switch can also be coupled to the directional control valve via differently designed line connections or via radio links, so that the directional control valve can be coupled to the switch via electrical signal lines and can communicate. However, this need not necessarily be formed by a physically existing switch on the device, but can also be a virtual component in a complex controller and / or a remote control, which increases the security against incorrect operations and the switching speed and thus the response times to external changes in state can be reduced. This may, for example, then have a positive effect if the vibrations that normally occur during operation of such a hand tool can lead to impairing the user's reaction or his ability to concentrate.

The electrical energy which is used to supply the circuit and / or to actuate the electromagnetically, piezoelectrically or otherwise precontrolled 5/3-way valve or possibly further existing and hereinafter referred to components (such as, for example, a radio module and / or a microprocessor control ) is required, can either be provided by built-in hand tools batteries or accumulators or via a supply from an external source, for example. By connection to a voltage source, which in turn is connected to the public power grid and which for the switching process the pre-controlled 5/3-way valve and optionally able to provide the available for the operation of other components electrical power. If an external power source for the electrical power supply is to be used, it makes sense to couple the leads for this purpose with the air line, for example. By integration of insulated electrical lines in the outer shell of a compressed air line leading to the impact wrench and is pneumatically coupled with this ,

To control the selected operating mode and / or the correct function, it may be advantageous to equip the hand tool according to the invention with display means which can transmit the corresponding information by optical and / or mechanical and / or acoustic means to the user and possibly other persons. Suitable display means may e.g. Display window with mechanically adjustable sliding elements, which v. A. with manual operation of the directional slide can be useful. Lamps, in particular light-emitting diodes, so-called LEDs, which supply the relevant information by means of different colors, flash sequences, or the like, may be particularly suitable. can provide. Display elements with an alphanumeric display function are also conceivable, as well as those which can display a larger amount of information on a display mounted on the device or in this integrated display.

In a further advantageous variant of the hand tool according to the invention, between or in addition to the at least one actuating element and the directional control valve Further intervention options and / or interfaces for more complex controls such as remote control, automatic direction of rotation, automatic shutdown upon reaching an adjustable limit torque, etc. may be provided, which may be considered in the electrical circuit. This may, for example, be provided that the more complex control can be coupled with a particularly advantageous to be combined with the device torque detection to open in this way further intervention options, such as a shutdown after reaching a definable limit torque o. The like.

In this context, it can also be useful to equip the hand tool according to the invention with a control and monitoring device, which can provide the data provided by the hand tool or its sensor system, which may be in the form of voltage values, pulse numbers, revolution numbers, time values, etc. evaluates. For this purpose, it is assumed that the hand tool has the sensors required for the detection and transmission and the transmission means required for the transmission of the determined data. The control and monitoring device itself is usually formed by a microcontroller unit, which evaluates the available data and transferred in convertible for the existing actuators control commands.

Alternatively or additionally, the hand tool according to the invention can be connected to an external control and / or control device via a wired and / or wireless path, which converts the data transmitted by the hand tool or its sensor into a form that can be evaluated for further processing, and in this way generally accessible by software evaluation. If necessary, the control commands resulting from the evaluation can be transmitted again in the same way to the hand tool according to the invention or its actuators and / or external devices connected to the hand tool by electrical, optical or pneumatic cables and / or lines and executed by them ,

Furthermore, it may be provided that the data transmitted to the external control and / or monitoring device is stored in and stored there for further evaluation, starting from a larger database.

It may also be possible that conclusions are derived from a directly performed evaluation, which conclusions can lead directly and / or subsequently to the same and / or different courses of action. Thus, for example, the determination of a limit torque may be provided, beyond which the impact wrench according to the invention receives a stop command from the integrated or external control unit and as a result terminates the tightening or loosening process. By combining with another parameter, e.g. the number of revolutions of the tool shaft required for the respective operation, further decision patterns can be derived and defined, e.g. a speed and / or torque control, reverse rotation and much more.

Starting from one of the abovementioned possibilities or a combination of several of the above, it may now be that components which were previously indispensable for the operation of the impact wrench and therefore were an integral part of the overall design, now flexible in or on the impact wrench or even can be arranged away from it; In particular, it may also be that suitable mechanical components can be replaced by electronic components and / or switching commands. So it can be e.g. be possible that the adjustment of the direction of rotation of the tool shaft can be made in various ways, be it by installing a corresponding mechanical switch o.ä. in the impact wrench itself, by incorporating an electronic switch / button in the device, by providing the function by an external device such as a foot switch and / or by transmitting the choice of the direction of rotation by an external control and / or control device, so that the choice the direction of rotation of the tool shaft manually by the operator of the hand tool and / or automated by a control and / or monitoring device, possibly also - depending on other influencing parameters - can be made by both.

This type of control makes it possible to automate work processes partially or even almost completely. For example. the external control and / or monitoring device can determine the successful loosening of a screw via suitable parameters, such as measuring the number of revolutions of the tool shaft, or the like, determining the torque, measuring a time interval, etc., automatically switch off the hand tool and set the direction of rotation Select "Tighten" without the operator having to act for this purpose. The latter can therefore already prepare for the "tightening process" and start the process as soon as the prerequisites have been met. Likewise, the end of this process can now be determined, for example, by reaching a predetermined torque, after which the hand tool can be switched off automatically. It is also possible that the shutdown of the tool immediately after the Tighten the screw as a signal to release the vehicle can serve without the operator of the tool must be in this regard.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

1 shows a schematic view of an embodiment of an impact wrench according to the invention.

2 shows a schematic diagram of a first variant of a valve for controlling the impact wrench according to 1 ,

3 shows a schematic diagram of a second variant of a valve for controlling the impact wrench according to 1 ,

4 shows a schematic diagram of a third embodiment of a controller for the impact wrench.

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are only examples of how the device according to the invention can be designed and do not represent a final limitation.

The schematic representation of 1 shows a possible practical embodiment of a hand tool according to the invention using the example of a striking screwdriver 10 in a housing 12 a rotationally acting compressed air drive having a front side of the housing 12 lead out tool shaft 14 can be placed in a rotation. In the embodiment shown, the tool shaft 14 a square fit 16 for attaching commercially available tool attachments (not shown), which may, for example, have a common customs measure. At a bottom of the elongated tool housing 12 There is a pistol-like handle 18 , the Einhandführung and -betätigung of impact wrench 10 allows. Inside the case 12 Furthermore, there is a hammer mechanism, not shown here, which is the generation or exercise of a direction of rotation on the tool shaft 14 acting periodic impact function. Possibly. the impact function of the impact mechanism can be switched off.

At the handle 18 is still one in the presentation of 1 designed as a probe element actuating element 20 provided by manual intervention or preselection of the rotary acting pneumatic drive for the tool shaft 14 and / or the radially acting impact function and / or the preselection of a direction of rotation of the tool shaft 14 can be activated or adjusted. The actuator 20 or the actuators 20 can, for example, be designed as a pressure switch, as a slide switch o. The like., Which via electrical connection lines with a controller for the impact wrench 10 are coupled. That behind the handle 18 at a lower portion of the rear end face of the housing 12 arranged further actuator 21 can be a direction switch. The presentation of the 1 This is based on the configuration of conventional impact wrenches, which have a mechanical slide switch to select the direction of rotation. However, it should be stressed at this point that only a simple variant, which in 2 is shown as a circuit diagram, has such a or similar slider, whereas electrical or microprocessor-controlled direction switches or a configuration according to 3 no such actuator 21 need. Therefore, it should be noted that the hand tool or impact wrench 10 in such an embodiment (eg according to 3 ) no such slide on the housing 12 but will have either a smaller or more inconspicuous switch or no externally detectable switching element, since its functions are taken over by the microprocessor control or eg by a radio remote control.

At a bottom of the gun-like handle 18 there is a compressed air connection 22 to the compressed air supply of the impact wrench 10 via a compressed air line 24 which, for example, may be in communication with a stationary or mobile pressure supply such as a compressor or optionally also with a refillable pressure accumulator (not shown).

In the embodiment shown is located on one of the lead-out tool shaft 14 with the square fitting 16 opposite rear end face of the housing 12 for example, an electromagnetically or piezoelectrically or otherwise pilot-controlled 5/3-way valve 26 for activation and for controlling the functions of the hand tool or impact wrench 10 that with the at least one actuating element 20 and / or the further actuating element 21 operatively connected and controllable by this. According to the present invention, the control valve is a pilot-operated 5/3-way valve 26 , which via electrical line connections with the at least one actuator 20 and / or with the further actuating element 21 or with other switching elements (see 4 ) is coupled, so that by a manual or automated operation of the switch or actuator 20 and or 21 in previously preselected direction of rotation, the tool shaft 14 is set in rotation.

The valve may also be a simple pilot operated, for example, a pneumatically pilot operated 5/3-way valve 28 Act as it is in the 2 in its meaningful connection as the simplest variant of a function control for the impact wrench 10 is shown. Here is the further actuator 21 makes sense as a manual directional slide, the at the in 1 seat shown and functional and spatially the valve 28 assigned. The switch on the handle 18 ie the first actuator 20 acts as a slide, seat or ball valve o. The like., Or as a release switch, with an electrical control for switching on or off the supply pressure for the drive of impact wrench 10 is coupled.

The schematic representation of 2 shows a simplest embodiment of a wiring of a 5/3-way valve 28 with pneumatic actuation or precontrol, as in the impact wrench according to the invention 10 can be used in principle. As the circuit diagram shows, the control switch is located 40 in the control pressure line 48 , which at the same time illustrates the impending throttle losses, which brings such an arrangement with it. The main pressure line, not shown here, passes through the handle of the impact wrench 10 (see. 1 ) and opens in the middle of the 5/3-way valve 28 , namely at the central main pressure port P.

The above recognizable direction of rotation switch is by the second actuator 21 formed, which the pilot control lines 49 for the pilot control of the shown 5/3-way valve 28 with the control pressure line 48 combines. The 5/3-way valve 28 is according to the 2 switched mechanically or pneumatically. The direction of rotation switch or the second actuator 21 is a pure switch, which is one of the two pilot control lines 49 pressurized and the other pilot control line 49 locked, leaving the control piston 44 is pressed in the appropriate direction, resulting in the connection diagram shown below for a standstill or for one of the two directions of rotation of the drive motor of the impact wrench 10 results.

Although the advantage of such a configuration is that all switching functions are controlled purely pneumatically, so that can be dispensed with an additional electrical power supply. However, the control switch can 40 in the control pressure line 48 as well as the switch 21 There are drawbacks associated with throttling losses, which, depending on the configuration, make it necessary to work with higher overall pneumatic pressures to compensate for throttling losses.

The presentation of the 3 illustrates the interconnection of an electromagnetically piloted 5/3-way valve 26 for controlling the rotating tool shaft 14 the impact wrench 10 , As mentioned, the 5/3-way valve 26 an electromagnetic, a piezoelectric, an electric motor or otherwise acting pilot control 30 exhibit. The diagram of such a 5/3-way valve 26 is below the sectional view of the valve 26 indicated; There it can be seen that it is a valve 26 with three switch positions and a total of five different pressure connections to be interconnected, whereby both the activation of the rotary actuator and its direction of rotation selection is possible. Above the sectional view of the valve 26 are electrical symbols of the actuating element 20 indicated, via an electrical connection to the pilot control 30 of the valve 26 a preselection of the direction of rotation as well as an on and off of the rotary drive of the impact wrench 10 enable.

Like the upper part of the 3 with the electrical circuit components, requires the 5/3-way valve 26 very few components, in their entirety the actuator 20 can form. These are an electrical power supply, for example in the form of a battery or a rechargeable battery, a push-button for activating the compressed air drive, with the pilot control 30 of the 5/3-way valve 26 is coupled and interacts with this. In addition, a switch for the direction of rotation is required, which may be formed as in the embodiment shown by a simple electrical switch.

The presentation of the 4 illustrates a more advantageous further expansion stage of the impact wrench according to the invention 10 due to its electrical feed forward 30 for the 5/3-way valve 26 especially good for wiring with a microprocessor control 32 suitable. This can not just be an interface 34 to deliver a CAN bus, but also all other switching and / or shutdown functions (wiring 36 ), including an automatic shutdown upon reaching or exceeding a definable limit torque. Also radio links to a central monitoring station is through such a microprocessor control 32 allows. Thus, numerous other functions are conceivable, such as logging of the occurring moments, automatic shutdown, speed control, etc.

Defined target torques allow, if necessary, central monitoring and / or influencing from a remote control or control center or control room.

The invention has been described with reference to a preferred embodiment. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

10

 Impact wrench, hand tools

12

 Housing, tool housing

14

 tool shaft

16

 Vierkantpassung

18

 Handle, tool handle

20

 Actuator, switch

21

 further actuator, reversal of direction of rotation

22

 Compressed air connection

24

 Compressed air line

26

 5/3-way valve (electromagnetically, piezoelectrically or similar pre-controlled)

28

 5/3-way valve (simply pre-controlled)

30

 feedforward

32

 microprocessor control

34

 interface

36

 further wiring

40

 control switch

44

 spool

48

 Control pressure line

49

 pilot line

Claims (11)

Pneumatically operated hand tool ( 10 ) with rotating tool shaft ( 14 ) with a percussion mechanism for generating or exerting in the radial direction on the tool shaft ( 14 ) periodic impact function is coupled, with at least one actuating element ( 20 ) for manual activation of the rotationally acting pneumatic drive for the tool shaft ( 14 ) and / or the radially acting impact function and / or for preselecting a direction of rotation of the tool shaft ( 14 ), whereby between a compressed air connection ( 22 ) of the hand tool ( 10 ) and the pneumatic drive of the tool shaft ( 14 ) at least one pilot operated 5/3-way valve ( 26 ) for activating and controlling the functions of the hand tool ( 10 ) arranged with the at least one actuating element ( 20 ) is operatively connected and is controlled by this or this. Hand tool according to claim 1, wherein the pilot-operated 5/3-way valve ( 26 ) is precontrolled electromagnetically or piezoelectrically or by electric motor. Hand tool according to claim 2, wherein the pilot control lines of the 5/3-way valve ( 26 ) in each case electromagnetic and / or piezoelectric controls or pilot controls ( 30 ) exhibit. Hand tool according to one of claims 1 to 3, wherein the actuating element ( 20 ) is formed by at least one electrical switch. Hand tool according to one of claims 1 to 4, wherein the actuating element ( 20 ) on the hand tool ( 10 ), in particular on a tool handle ( 18 ). Hand tool according to one of claims 1 to 4, wherein the actuating element ( 20 ) with an electronic circuit and / or microprocessor control ( 32 ) is coupled. Hand tool according to one of claims 1 to 6, wherein between the at least one actuating element ( 20 ) and the 5/3-way valve ( 26 ) further intervention options and / or interfaces for more complex control systems ( 32 ) are arranged, which are taken into account in the electrical circuit. Hand tool according to Claim 7, in which the more complex control ( 32 ) with a hand tool ( 10 ) implemented existing torque detection is coupled. A hand tool according to claim 6 or 7, wherein the more complex control or microprocessor control ( 32 ) with a reversal of the direction of rotation for the pneumatic drive for the tool shaft ( 14 ), which works with the 5/3-way valve ( 26 ) coupled or can be triggered by this. Hand tool according to Claim 8 or 9, in which the impact function and / or the drive of the tool shaft ( 14 ) is coupled to the torque detection such that at least one of the functions is automatically switched off upon reaching a presettable limit torque. Hand tool according to one of Claims 6 to 10, in which the more complex control or microprocessor control ( 32 ) via a wireless data connection with a switching and / or monitoring center can be coupled and / or controlled.

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