Patent Publication Number: US-11648651-B2

Title: Installation tool for a wire thread insert

Description:
1. TECHNICAL FIELD 
     The present disclosure is related to an installation tool for a wire thread insert, a torque clutch which can be used in such tools as well as an installation method for a wire thread insert in a thread bore. 
     2. BACKGROUND 
     In the state of the art, installation tools with a rotating drive unit are generally known. Such installation tools are for example used for installing wire thread inserts in a thread bore, for screwing in a thread bolt or for tightening or loosening a female thread element on a thread bolt or the like. In this connection, pneumatic or electric engines serve as drive units. It is also conceivable that such installation tools be driven manually. 
     In order to avoid an overload condition when screwing in a thread bolt or during another connection that is to be made in a rotating manner, torque clutches are used in the state of the art. Such clutches are also referred to as overload clutches, as is described in DE 195 01 084 C2. The overload clutch illustrated there is used in a force-driven or engine-driven tool. This overload clutch is configured of driving clutch parts and driven clutch parts. The driving and driven clutch parts are connected with each other through spring means and a pretension force being generated in this connection. The clutch parts which are spring-pretensioned against each other include inlet and outlet cam discs which are arranged axially opposite to each other. Furthermore, clutch balls are arranged between those inlet and outlet cam discs, with these clutch balls interacting with the cams such that a releasable drive between the rotary drive inlet and the rotary drive outlet takes place. As soon as a critical torque has been reached, the clutch parts being spring-pretensioned against each other of the overload clutch interrupt the force flow between the drive side and the output side. In this way, it is avoided that an overload torque reaches the connection to be established and causes damages there. 
     While DE 195 01 084 C2 describes an overload clutch in combination with an electric engine, a torque clutch in combination with a switch-off mechanism for a pneumatic drive unit is described in U.S, Pat. No. 3,442,362. In this state of the art, too, the goal is that the transmission of a too big torque onto a connection to be established is avoided in due time, so that this connection but also the tool are not damaged. 
     Known overload clutches operate with clutch balls which are arranged between the spring-pretensioned clutch parts that are arranged opposite to each other. These clutch balls provide for a low friction between the clutch balls which realize the force flow and which are detachable from each other. At the same time, such a complex construction of an overload clutch causes a high effort in manufacturing and maintenance. 
     With regard to installation tools for wire thread inserts, it has become apparent that an interruption of the torque transmission alone when reaching a depth stop of the installation mandrel of the installation tool is not sufficient for realizing a comfortable installation. Rather, constructions of wire thread inserts meanwhile require a targeted release or separation of the installation mandrel from the screwed-in wire thread insert or also a targeted bending back of parts of the wire thread insert. For example, a wire thread insert with installation tangs is installed in a way that the installation mandrel generates a form-fit connection with the installation tang for screwing in the wire thread insert. In order to be able to release the mandrel from the thread opening again, the installation tang must be released from this form-fit connection. 
     A wire thread insert without installation tangs, having a dragging notch at a radial inner side, requires an installation blade in order to be able to screw in this wire thread insert into the thread bore. After having screwed the wire thread insert into the desired depth, this installation blade must be released from the engagement with the wire thread insert by suitably actuating the installation tool. Only then can a targeted reverse-rotation or screwing or rotation of the mandrel out of the thread opening take place. 
     The wire thread insert which is described in DE 10 2010 050 735 requires, after being screwed into the desired depth of the thread opening, a targeted bending back of its installation tang. Accordingly, it is necessary that an installation blade attaches to this installation tang which can be bent back, in order to bend it back into the thread of the thread opening. Only when this additional installation step has been completed should the installation mandrel be removed from the thread opening. 
     Based on the specific requirements for installation tools for wire thread inserts, it is the object of at least some implementations of the present invention to provide an installation tool for installing wire thread inserts, which, besides the protection against an overload torque, also automatically enables the realization of additional installation steps. 
     3. SUMMARY 
     The above object is solved by an installation tool for a wire thread insert  1 , by a torque clutch being inserted into this installation tool as well as by an installation method for a wire thread insert into a thread opening with the help of the above-mentioned installation tool. Further embodiments, developments and modifications of the present disclosure are set forth in and apparent from the following description, the accompanying drawings as well as the appending claims. 
     The wire thread insert installation tool comprises the following features: a drive unit, in particular an electric or pneumatic drive unit, providing a switchable rotation movement switchable between a first and a second direction, a mandrel body with a driving section for rotating the mandrel body and with a thread section onto which the wire thread insert can be screwed or rotated and from which the wire thread insert can be rotated, an installation blade which is arranged movably in the mandrel body between an engagement position and a rest position in order to attach at the wire thread insert in a targeted manner and/or to release itself from an attachment or engagement at the wire thread insert, and a torque clutch which consists of a clutch upper part and clutch lower part engaging into each other in a form-fit and force-fit manner, of which the clutch upper part is connected torque-proof with the drive unit and the clutch lower part is connected torque-proof with the mandrel body, while a relative movement, in particular a linear relative movement, between the mandrel body and the installation blade can be generated with a de-clutched or decoupled relative rotation between the clutch upper part and the clutch lower part, caused by exceeding a predetermined limit torque between the clutch upper part and the clutch lower part. 
     Due to its configuration, the above installation tool for a wire thread insert first of all supports the prevention of torque overload conditions when inserting or installing or screwing in the wire thread insert into a thread opening, as the used torque clutch releases the connection between the drive side and the output side of the installation tool as soon as a critical torque, e.g. when the installation mandrel runs aground an axial stop, is reached. With this releasing movement of the torque clutch, an actuation movement, which may be a linear actuation movement, between one of the clutch halves and a movable actuator is, however, also caused at the same time. These clutch halves are formed by the above-mentioned clutch upper part and the clutch lower part. That means that while an overload condition during the rotation movement causes the connection between the clutch upper part and the clutch lower part to be released, an axial movement along a rotation axis of the clutch upper part and the clutch lower part may be caused at the same time. 
     This axial relative movement between the mentioned actuator and the clutch upper part and/or the clutch lower part can be used for a further work step during the installation of the wire thread insert into a thread bore. This axial relative movement of the actuator may be used when releasing an installation blade of the installation tool from an engagement with the wire thread insert. Another alternative is to displace the installation blade in an engagement position or in another assembly position within the installation mandrel and/or at the wire thread insert. A further embodiment is that by means of the axial relative movement of the actuator, besides an installation blade, a further adjustment element is actuated. This actuation element can for example be used for releasing the installation tang from an engagement of the installation mandrel. 
     According to a further embodiment of the installation tool, the clutch lower part and the clutch upper part are arranged in a spring-pretensioned manner against each other so that in case of a rotation blockage of the clutch lower part via the mandrel body, the clutch upper part can be rotated with respect to the clutch lower part, with the clutch lower part giving way in a springy manner. 
     Due to the design of the sides of the clutch lower part and clutch upper part which face each other, both clutch parts form a form-fit and/or force-fit connection supported by spring-pretension. The spring pretension which is impressed into the clutch parts determines an actuation torque between the two clutch parts, causing a release of the connection between the clutch lower part and the clutch upper part. This release of the clutch parts from each other takes place precisely when the mentioned rotation blockage of the clutch lower part or the clutch upper part occurs. 
     According to the present disclosure, it may be preferred that the clutch lower part is connected with the mandrel body, so that a rotation blockage of the mandrel body causes a standstill of the clutch lower part. The clutch upper part may be further rotated by the drive unit, exceeding a critical torque between both clutch parts leads to overcoming the spring pretension between the clutch lower part and the clutch upper part. Accordingly, the clutch upper part then continues to rotate compared with the clutch lower part, which causes the torque clutch to release. The provided spring pretension between the clutch lower part and the clutch upper part thus offers the possibility that the clutch lower part may give way to a continued rotation of the clutch upper part by means of an axial displacement. 
     According to a further embodiment of the installation tool, the clutch upper part comprises a link motion or link guide with which an axial actuator of the clutch upper part in dependency of the rotation direction of the clutch upper part can be axially displaced, with the axial actuator not co-rotating with the clutch upper part. In this connection, it may furthermore be preferred that the axial actuator is a clutch piston guided axially in the clutch upper part with an at least one-sided radially protruding roller pin which engages into the link guide. 
     The wire thread insert installation tool is provided such that the mandrel for installing the wire thread insert is connected with the clutch lower part. Accordingly, the mandrel and thus the clutch lower part, too, are blocked during installation as soon as a certain installation depth or an axial stop of the mandrel has been reached. In this situation, the rotation blockage of the mandrel leads to a rotation standstill of the clutch lower part, it does, however, not prevent a further rotation of the clutch upper part due to the arising overload torque. 
     As the clutch upper part rotates relative with respect to the centrally arranged clutch piston, the link guide which is connected in a form-fit manner with the clutch piston leads to an axial displacement of the clutch piston. This movement, which can be understood as a secondary use of the actuation movement between the clutch upper part and the clutch lower part is used for the targeted movement or a switching or actuation of an axial actuator in the present disclosure. Depending on the design of the link guide, which may determine a movement path of the engaging roller pin here, the movement profile of the axial actuator can be defined. 
     According to a further embodiment, the link guide defines a curvilinear path, in particular a helix path, in the clutch upper part, which causes a relative axial displacement between the clutch upper part and the clutch piston when the clutch upper part is rotated relative to the clutch piston. 
     Depending on the preferred circumferential course of the link guide, a direction, a size of an axial displacement as well as a speed of an axial displacement taking place can be adjusted. It therefore may be preferred that the movement of the actuator is adjusted or adapted to the installation function to be realized of the installation tool via the shape of the link guide. 
     According to a further embodiment of the wire thread insert installation tool, the axial displacement of the clutch piston can be transferred to the installation blade via an actuator. The installation blade, which is arranged within the mandrel body, is used during installation of a wire thread insert and/or during an uninstallation of the wire thread insert or during a processing of the wire thread insert in the thread opening. Accordingly, the moved actuator and the movement which has been transferred to the installation blade is used for carrying out installation steps, processing steps and/or uninstallation steps at a wire thread insert in a thread opening. 
     According to a further embodiment of the wire thread insert installation tool, the above-mentioned axial displacement takes place depending on the rotation direction of the clutch upper part compared with the clutch lower part into the direction of the mandrel body or into the direction of the drive unit. According to the disclosure, it may furthermore be preferred that the clutch upper part and the clutch lower each comprise, in an axial orientation of face sides opposite to each other, a circumferential sequence of at least two contra-directional ramps being adjacent with respect to a common vertex, with the ramps defining an engagement contour between the clutch upper part and the clutch lower part. 
     Besides the spring pretension between the clutch upper part and the clutch lower part, which was already discussed above, the strength of the releasable connection between the clutch upper part and the clutch lower part is also determined by the engaging contours of the surfaces facing each other or face sides, respectively, of the clutch upper part and the clutch lower part. According to the disclosure, these surfaces of clutch upper part and clutch lower part each include at least one cam which comprises two contra-directional ramps which are connected via the common vertex. An inclination of these ramps as well as the spring pretension which presses the clutch upper part and the clutch lower part against each other, define a release torque which enables the clutch upper part to glide away in a rotating manner on the rotation-blocked clutch lower part. Depending on the application area of the installation tool, the shaping contour of the facing sides of the clutch upper part and the clutch lower parts as well as the strength of the spring pretension between the clutch upper part and the clutch lower part can be chosen and/or adjusted in a targeted manner. 
     In connection with the above description, it may therefore also be preferred that an inclination angle of the ramps in combination with the spring pretension between the clutch upper part and the clutch lower part determines a limit torque at which a relative movement between the clutch upper part and the clutch lower part can be generated. 
     The present disclosure also includes the torque clutch which is used in the above described wire thread insert installation tool. This torque clutch can also be used for other tools in which a rotating drive unit is used. This torque clutch comprises the following features: clutch upper part and clutch lower part engaging with each other in a form-fit and force-fit manner, of which the clutch upper part or the clutch lower part can be connected in a torque-proof manner with a drive unit and the other clutch part can be connected in a torque-proof manner with an output unit, while with an uncoupled relative rotation between the clutch upper part and the clutch lower part caused by exceeding a limit torque between the clutch upper part and the clutch lower part, a linear relative movement between the clutch part that is clutched to the drive unit and an actuation unit that is arranged in this clutch part and is axially moveable can be generated. 
     According to a further embodiment, the torque clutch comprises the feature that the clutch lower part and the clutch upper part are arranged against each other in a spring-pretensioned manner so that in case of a rotation blockage of the clutch lower part, the clutch upper part can be rotated with respect to the clutch lower part. This configuration ensures that the torque clutch effectively releases the connection between the clutch lower part and the clutch upper part when a critical torque is exceeded. 
     It may furthermore be preferred that the clutch upper part comprises a link guide with which an axial actuator of the clutch upper part can be axially displaced relative to the actuator depending on a rotation direction of the clutch upper part. It may furthermore be preferred that the axial actuator is a clutch piston that is guided axially in the clutch upper part, having at least a one-sided radially protruding roller pin which engages into the above-mentioned link guide. In this connection, it may be preferred that the link guide is defined as a curvilinear path, in particular a helix path, in the clutch upper part which causes a relative axial displacement between the clutch upper part and the clutch piston when the clutch upper part is rotated. 
     In order to be able to use this relative axial displacement between the clutch upper part and the clutch piston, it can be transferred via an actuator to the actuation unit, in particular to an actuation unit that is arranged within the drive unit. Furthermore, the axial displacement may take place depending on the rotation direction of the clutch upper part compared with the clutch lower part into the direction of the output unit or into the direction of the drive unit. 
     As already described above in combination with the installation tool for a wire thread insert, the clutch upper part and the clutch lower part each comprise, in an axial orientation opposite to each other, a circumferential sequence of at least two contra-directional ramps being adjacent with respect to a common vertex, with the ramps defining an engagement contour, such as a direct engagement contour, between the clutch upper part and the clutch lower part. The used inclination angle of the ramps into the direction of the vertex generate, in combination with a spring pretension between the clutch upper part and the clutch lower part, a limit torque, at which a relative rotation between the clutch upper part and the clutch lower part and a relative displacement between an actuator and the clutch upper part or the clutch lower part can be generated. 
     Furthermore, the present disclosure includes an installation method for a wire thread insert in a thread opening with an installation tool according to one of the above described embodiments. The installation method comprises the following steps: rotating or screwing the wire thread insert on the mandrel body in a first rotation direction of the mandrel body, placing the mandrel body with the wire thread insert in position at the thread opening and screwing in the wire thread insert into the thread opening with the help of the mandrel body by rotating the mandrel body in the first rotation direction until a stop blocks a further axial screwing of the mandrel body, actuating the torque clutch by blocking the mandrel body so that the installation blade is put, via a relative movement to the mandrel body, into an attachment position/operation position or is put from the operation position into a rest position, and rotating the mandrel body in a second rotation direction until the wire thread insert is rotated off from the mandrel body. 
     The installation method that may be preferred for a wire thread insert uses the above-described advantageous features of the installation tool with torque clutch. A wire thread insert is usually screwed into the thread opening with the help of the installation tool so deep until the mandrel of the installation tool is blocked from a further rotation movement by a depth stop. This depth stop determines up to which depth the wire thread insert should be installed in the thread opening. However, at the same time, the blockage of the rotation movement of the mandrel leads to the prevention of a further common rotation of the clutch upper part and clutch lower part due to the releasable form-fit and force-fit connection present between them. As, however, there is still an operation connection between the drive unit and the torque clutch, the clutch upper part continues to rotate despite the rotation blockage of the clutch lower part, so that the torque clutch releases the connection between the mandrel body and the drive unit. By releasing this operation connection between the drive unit and the mandrel body, an axial relative movement between the clutch upper part and a clutch piston that may be arranged therein is caused at the same time. This clutch piston is held radially in a link guide which converts the continuing rotation movement of the clutch upper part into an axial relative movement between the clutch piston and the clutch upper part. This axial relative movement can be transferred to the mandrel body and the installation blade arranged therein and is transferable into a movement of the installation blade. 
     Furthermore, the installation method may comprise the further step: bending back an installation tang of the wire thread insert into a thread of the thread opening by means of the installation blade that is displaced in an attachment position during rotation in the second rotation direction. Furthermore, a compression of the installation tang after bending back and switching of the torque clutch when a limit torque is reached occurs in combination with a displacing of the installation blade from an attachment position at the wire thread insert into a rest position. According to a further embodiment of the installation method, a manual or an automatic switch between the first and the second rotation direction takes place. 
    
    
     
       4. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       The embodiments of the present disclosure are described in more detail with reference to the accompanying drawings. It shows: 
         FIGS.  1   a  and  1   b    are exploded views of an embodiment of the installation tool, 
         FIG.  2    a sectional side view of an embodiment of the installation tool, 
         FIG.  3    a further sectional side view of the installation tool, 
         FIG.  4    an illustration of a first movement sequence of the installation tool when the wire thread insert is screwed into a thread opening, 
         FIG.  5    a further movement sequence of the installation tool when the further rotation of the mandrel body is blocked due to the depth stop, 
         FIG.  6    an illustration of a subsequent movement sequence to a blockage of the mandrel body due to the depth stop, 
         FIG.  7    a sectional view of an embodiment according to  FIG.  6    with respect to the illustration of the inner motion cycles in the installation tool, 
         FIG.  8    an illustration of a further motion sequence of the installation tool when rotating back the mandrel body, 
         FIG.  9    an illustration of a further motion sequence while rotating back the installation tool, 
         FIG.  10    a sectional view of an embodiment of the installation tool according to  FIG.  9    with respect to the illustration of the inner motion processes in the installation tool, 
         FIG.  11    an illustration of a further motion sequence of the installation tool while being rotated back, 
         FIG.  12    an embodiment of the anti-interference blockage of the installation tool, 
         FIG.  13    an illustration of the control of the installation tool when using the anti-interference function, 
         FIG.  14    an illustration of the motion cycles while using the anti-interference function, and 
         FIG.  15    a flow chart of an embodiment of the installation method. 
     
    
    
     5. DETAILED DESCRIPTION 
     With respect to  FIG.  1   , the construction of the installation tool  1  for a wire thread insert is shown based on the exploded view. The installation tool  1  includes a drive unit  10 . The drive unit  10  may be driven electrically or pneumatically. It furthermore may comprise a start switch  12  in order to switch on or switch off the drive unit  10 . Accordingly, the mandrel body  20  starts to rotate or interrupts its rotation when the start switch  12  is actuated. The drive unit  10  furthermore may include a rotation direction change switch  14 . When it may be actuated in combination with the start switch  12 , the rotation direction of the drive unit  10  reverses. 
     The mandrel body  20  includes a thread section  22  facing away from the drive unit  10 . The wire thread insert to be installed is rotated or screwed on or from it. 
     The mandrel body has an inner hollow space in which a slider  24  is arranged. The slider  24  can be axially displaced via the actuation of a torque clutch or torque arrangement  30 , respectively, as described in more detail below. 
     An opening to the inner hollow space of the mandrel body  20  is provided at an installation end of the mandrel body  20  which faces away from the drive unit  10 . Accordingly, an installation blade  28  or the slider  24  may grip from the inside of the mandrel body  20  to the outside at this location in a displaceable manner. The installation end furthermore may include an installation structure in order to hold a wire thread insert on the thread section  22  in a torque-proof manner. The installation structure for a wire thread insert with a tang that can be bent back is described in DE 10 2010 050 735 and is incorporated by reference. For a wire thread insert with a radially extending installation tang, the installation structure alternatively consists of a radially extending depression or groove. Furthermore, the installation blade  28  can be used as the installation structure, the blade engaging into a notch that is arranged at a radial inner side of the wire thread insert. 
     A depth stop  26  may be arranged on the thread section  22 . When the thread section  22  with wire thread insert is screwed into a thread opening up to the depth stop  26 , the depth stop  26  blocks a further screwing-in as well as a further rotation of the mandrel body  20  in the screw-in direction or installation direction R I , respectively. 
     The clutch arrangement  30  is provided within a housing Gin which the mandrel body  20  is held in a rotatable manner. The clutch arrangement  30  establishes a releasable connection between the drive unit  10  and the mandrel body  20 . This releasable connection transfers the rotation movement of the drive unit  10  onto the mandrel body  20  or interrupts the force flow between the drive unit  10  and the mandrel body  20 . 
     The torque clutch  30  may include a clutch lower part  32  which is spring-pretensioned against a clutch upper part  34 . The spring pretension is generated by a spring  36 . A clutch surface  38 ,  40  may be provided at the clutch upper part  34  and clutch lower part  32  each. These clutch surfaces  38 ,  40  face each other and are pressed against each other via the spring  36  in a releasable manner. Depending on the design of the clutch surfaces  38 ,  40 , a form-fit and a force-fit connection between the clutch upper part  34  and the clutch lower part  32  arises, which transfers the rotation of the drive unit  10  onto the mandrel body  20 . 
     Each clutch surface  38 ,  40  may comprise at least one cam  39 ,  41 , two each, which are limited by adjacent valleys. Based on this shape, the clutch surfaces  38 ,  40  may fittingly engage into each other. In this connection, each cam  39 ,  41  comprises a vertex over which two contra-directionally inclined ramps are connected with each other. 
     In the configuration of the installation tool  1 , the clutch upper part  34  is connected with the drive unit  10  in a torque-proof manner. The clutch lower part  32  may be connected with the mandrel body  20  in a torque-proof manner. At the same time, the clutch lower part  32  is, however, deflectable against the force of the spring  36  in an axial direction, i.e. in the direction of the mandrel body  20 . 
     During the installation of the wire thread insert in the thread bore, the mandrel body  20  rotates with the wire thread insert in accordance with the thread direction of the receiving thread of the thread bore. As soon as the depth stop  26  runs aground the component with the thread bore, the mandrel body  20  is blocked from a further rotation. The torque, which is transferred by the drive unit  10  onto the clutch upper part  34  compared with the blocked clutch lower part  32 , now reaches a limit value so that the clutch upper part  34  is rotated relative with respect to the clutch lower part  32 . 
     The limit torque may be firstly determined by the pretension of the spring  36  between the clutch upper part  34  and the clutch lower part  32 . In this connection, it may for example also be preferred that the adjoining clutch surfaces  38 ,  40  are configured smooth. A friction connection between the two clutch surfaces  38 ,  40 , which would be determined by the surface friction alone, then sets the limit torque. For this purpose, the clutch surfaces  38 ,  40  may be also profiled or roughened. 
     According to the above-described embodiment, the clutch surfaces  38 ,  40  include engaging cams and valleys as they can be seen in  FIGS.  5 ,  6 ,  8   . A cam is correspondingly formed by two ramps extending towards one vertex. Depending on the inclination angle of the ramps which extend towards the common vertex, the limit torque of the torque clutch  30  can be adjusted. The steeper the ramps raise towards the vertex, the higher the limit torque must be in order to actuate the torque clutch  30 . 
     The clutch lower part  32  is provided with an axial hollow space. It serves for receiving and moving a pin-like slider linkage  42 . The slider linkage  42  may serve for transferring a linear movement along the longitudinal axis of the installation tool  1 . Here, the movement of a clutch piston  44  within the clutch upper part  34  is transferred via the slider  24  onto the installation blade  28  or directly onto the installation blade  28 . The slider  24  and the slider linkage  42  may be connected with the mandrel body  20  and/or the clutch lower part  32  in a torque-proof manner. Thus, they cannot be rotated against each other. 
     According to the disclosure, it may be preferred that the clutch upper part  34  is provided at least over an axial partial section as a hollow-cylindrical sleeve. In the inner cylindrical free space of the clutch upper part  34 , the clutch piston  44  is held in an axially displaceable manner. For that, the clutch piston  44  may comprise at least one roller pin  46  which protrudes radially to the outside. The roller pin  46  is firmly arranged in the clutch piston  44 . Furthermore, the roller pin  46  may be received and guided in a link motion or link guide  48  of the clutch upper part  34 . 
     If the clutch arrangement  30  is in an unreleased state, the clutch upper part  34  rotates together with the clutch piston  44  and the clutch lower part  32 . The rotation of the clutch piston  44  is based on the rotational dragging of the roller pin  46  by the link guide  48 . Due to the form-fit connection between the cams  39 ,  41  and the valleys of the clutch surfaces  38 ,  40 , the torque-proof connection of the clutch piston  44  with the mandrel body  20  arises through the slider linkage  42 . 
     As soon as the clutch arrangement  30  is actuated, the clutch upper part  34  rotates with respect to the clutch lower part  32  and the rotationally blocked mandrel body  20 . The clutch piston  44  may be connected with the clutch lower part  32  and/or the mandrel body  20  in a torque-proof manner. Thereby, the roller pin  46  remains in its rotation angle position while the link guide  48  of the clutch upper part  34  continues to move. As the link guide  48  comprises an inclination, the link guide  48  may be helically shaped, the clutch piston  44  is displaced in an axial direction in case of a relative movement between the clutch piston  44  and the clutch upper part  34 . The intensity and the direction of the axial displacement of the clutch piston  44  is determined by the inclination and the course of direction of the link guide  48 . 
     With reference to  FIG.  4   , firstly, the screwing-in of the wire thread insert into the thread opening is schematically illustrated (S 3 ), until the depth stop  26  comes to a blocking position on the component (not shown). For this purpose, the thread section  22  may comprise a right-handed thread so that the drive unit  10  operates in a right-rotating way for the installation (see arrows in  FIG.  4   ). In case of a left-handed thread on the thread section  22 , the movements that are necessary for the drive and the installation are correspondingly carried out in an opposite direction. 
     After the depth stop  26  blocking a further rotation of the mandrel body  20 , the clutch upper part  34  continues to rotate with respect to the clutch lower part  32  (see  FIG.  5   ). As the clutch piston  44  is connected with the clutch lower part  32  in a torque-proof manner, the link guide  48  rotates relative with respect to the roller pin  46  arranged therein (S 4 ). 
     According to the embodiment shown in  FIG.  5   , the link guide  48  has an inclination into the installation direction R I , similar to a left-handed thread. Thus, in case the link guide  48  is rotated to the right side around the clutch piston  44 , the link guide  48  displaces the clutch piston  44  via the roller pin  46  into the installation direction R I . The slider  24  is axially displaced with this axial movement in order to displace the installation blade  28  from the inside of the mandrel body  20  to the outside (S 4 ). By that, the further installation of the wire thread insert with tangs that may be bent back is prepared, as is described in DE 10 2010 050 735. Generally, moving out of the installation blade  28  is realized due to the axial movement of the clutch piston  44  into the installation direction R I . This movement may be also used for ejecting an installation tang of a wire thread insert from a radial groove at the installation end of the thread section  22 . 
     Analogously, it may also be preferred to move back an already moved-out installation blade  28  or an installation slider into the mandrel body  20 . For this purpose, in case of a right-rotating drive unit  10 , the link guide  48  may have the course similar to a right-handed thread. In this case, the relative movement between the clutch lower part  32  and the clutch upper part  34  would cause an axial displacement of the clutch piston  44  contrary to the installation direction R I . 
     In case of a left-rotating drive unit  10 , the link guide  48  would correspondingly have to be inclined in a contrary direction, i.e. in case of an axial displacement into the installation direction R I  similar to a right-handed thread and opposite to the installation direction R I  similar to a left-handed thread. 
     The displacement into the installation direction R I  is schematically also shown in  FIG.  7   . Here, it can be seen how the axial displacement of the clutch piston  44  is transferred to the slider  24  and the installation blade  28  via the slider linkage  42 .  FIG.  10    shows how a axial displacement contrary to the installation direction R I  takes place. As the clutch piston  44 , the slider linkage  42 , the slider  24  and the installation blade  28  may be axially coupled, the axial displacement of the clutch piston  44  leads to the installation blade  28  being retracted into the mandrel body  20 . 
     After displacing the installation blade  28 , the rotation direction of the drive unit  10  may be reversed (S 7 ). According to a further embodiment, this takes place by actuating or pressing the start switch  12  and the rotation direction change switch  14  at the same time. It may also be preferred that only one switch for this function be provided or that the rotation direction be changed automatically. According to a further embodiment, precisely no interlocking of the switch for the change of the rotation direction takes place when the rotation direction is changed. In this way, the handling and application of the installation tool is facilitated. 
     According to a further embodiment, the mandrel body  20  with moved-out installation blade  28  now rotates to the left after screwing-in the wire thread insert with tangs that can be bent back and a right-handed thread. As described in DE 10 2010 050 735 in connection with the installation method of the wire thread insert with tangs that can be bent back, which is incorporated herein by reference, the tang that can be bent back or with redressible tangs of the wire thread insert is bent back into the thread of the thread opening (S 5 ). 
     After that, a compression of the tang follows (S 6 ). During compression, the installation blade  28  pushes against the tang, thereby blocking a further rotation of the mandrel body  20 . This rotation blockage leads to an actuation of the clutch arrangement  30 , similar to a running aground of the depth stop  26  as described above. Accordingly, the course which is described with respect to  FIG.  5    takes place in a contrary direction, as is illustrated in  FIG.  9   . In this connection, the maximum torque with which the tang is compressed is regulated via the limit torque of the clutch arrangement  30 . 
     The rotation blockage of the mandrel body  20  also blocks the clutch lower part  32 . Accordingly, the clutch upper part  34  continues to rotate relative with respect to the clutch lower part  32  and axially displaces the clutch piston  44  contrary to the installation direction R I . 
     Due to the axial displacement contrary to the installation direction R I , the installation blade  28  is released from the engagement or attachment at the wire thread insert (S 6 ). Due to this, the rotation blockage of the mandrel body  20  is raised and the thread section  22  is rotated out from the installed wire thread insert (S 9 ). 
     Before the axial displacement of the installation blade  28  takes place, the installation blade  28  attaches to the end to be compressed of the wire thread insert. This attachment may be supported by a friction connection between the installation blade  28  and the end of the wire thread insert, which might make releasing the installation blade  28  by the mentioned axial displacement more difficult. It may therefore be preferred that a counter-rotation contrary to the pressing rotational movement takes place before the above-mentioned axial displacement in order to release the connection between the installation blade  28  and the wire thread insert. This counter-rotation comprises a rotation angle smaller than 360°, may be smaller than 180° or even smaller than 90°. Due to this counter-rotation, the installation blade  28  is released from the friction connection with the end to be compressed of the wire thread insert. This counter-rotation may relieve the installation blade  28 . Subsequently, the above-described axial displacement of the installation blade  28  may take place, with this movement not being interfered by friction losses. 
     In order to be able to start a new installation process, the rotation direction of the drive unit  10  is firstly switched in the thread direction of the thread section  22 . By that, a new wire thread insert can be rotated or screwed on the thread section  22  (S 1 ) and be installed subsequently. 
     During the installation of a wire thread insert, it can happen that the thread section  22  tilts within the thread opening of the component without installing the wire thread insert. Due to the tilting, the limit torque of the clutch arrangement  30  is exceeded and the clutch arrangement  30  actuates. Accordingly, the installation blade is now in a position in which it could interfere a removal out of the wire thread insert from the thread opening and/or the rotating off of the wire thread insert from the thread section  22 . 
     It may therefore be preferred that firstly, the mandrel body  20  be blocked in its rotation with the help of an anti-disruption or anti-interference blockage  50 . The anti-interference blockage  50  may be a pin which is pressed against a plane surface or into an impression or into a groove at the mandrel body  20 . The friction connection between the anti-interference blockage  50  and the mandrel body  20  which arises as a result prevents a rotation of the mandrel body  20 . In this connection, it may also be preferred that the clutch lower part  32  be blocked. In this way, the same function is achieved as is caused by the above-described pin  50 . 
     Now, the rotation direction of the drive unit  10  may be changed by simultaneously actuating the start switch  12  and the rotation direction change switch  14  (S 7 ). The drive unit  10  which is displaced into rotation by that leads to an exceeding of the limit torque, as the drive unit  10  tries to rotate the clutch upper part  34  against the retained clutch lower part  32 . Accordingly, the clutch arrangement  30  actuates and axially moves the clutch piston  44  and thus the installation blade  28  back into the start position. Now, the thread section  22  with the wire thread insert may be removed from the thread opening. Subsequently, it may be preferred that the wire thread insert which is still present on the thread section  22  is again installed in the thread opening. Alternatively, it may also be preferred that the wire thread insert which is still present on the thread section  22 , be removed and that a new wire thread insert be rotated on. After completing the rotating on, the wire thread insert which has been rotated on anew can be installed in the thread opening of the component.