Abstract:
Disclosed is a tightening tool for a screw element, having a tool receptacle and an associated line. A coupling part is provided, which is formed at a free end for engaging with the tool receptacle in a form-closed manner and transitions into a handle or can be coupled to a handle at the other end. The coupling part has an interior and at least one lateral opening for inserting or leading out the line at least at the free end of the coupling part. The interior and the opening extend to the free end and are open there. The invention further relates to a coupling part and to a screw element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the United States national phase of International Application No. PCT/EP2012/057410 filed Apr. 23, 2012, and claims priority to German Patent Application No. 102011018465.1 filed Apr. 21, 2011, the disclosures of which are hereby incorporated in their entirety by reference. 
     BACKGROUND 
     The present invention relates to a fastening tool for a screw element having a tool mount and an associated line, as well as to a coupling part for the fastening tool and to a screw element configured for a cooperation with the coupling part and/or the fastening tool. 
     Screw elements which serve for the attachment of a line to a counterpiece, be it to a connector to a further line or to a terminal at a housing of a device or to a pneumatic or hydraulic installation are known in a large variety. The connections can be inputs or outputs. The lines can be composed of metal and/or of plastic and can be configured rigid or flexible. The screw elements can have the shape of hollow bolts or of screw sockets or can be configured as a sleeve nut. Also screw elements for the fastening of electric lines to electric devices are used. Such screw elements frequently have the shape of hollow screw bolts which comprise a ring-shaped sealing element and/or a clamping element for the line, as well as a line guided through the sealing element. 
     In particular in the field of the analytical, preparatory or industrial chromatography and in the field of medical diagnostics and in the field of laboratory devices in general, relatively thin hoses of plastic, which in operation are frequently subjected to a high pressure, are frequently connected to the corresponding devices by means of a screw elements of plastic, for example, to HPLC devices, MPLC devices or LPLC devices and/or to chromatography columns. In this connection a considerable number of lines can be connected to a device. It happens time and again that the accessibility of the screw elements is difficult due to the limited spatial conditions. In this connection, it can indeed happen that corresponding screw elements can only be turned over small angular ranges. Under these circumstances it is also difficult to ensure that the screw elements are sufficiently tightened, however, not so tight that the thread of the screw element, which is frequently composed of plastic, is damaged or that the screw element is tightened so hard that the seal of the plastic hose is no longer ensured be it due to a deformation or a damaging of the hose and/or of a provided seal. 
     Furthermore, a problem exists with respect to screw elements in that, due to the narrow spatial conditions it, is striven for to make the screw elements themselves as small as possible. Since the lines which are guided through the screw elements take on a considerable areal region of the end face of the screw element and cannot always be made smaller, the space available for the attachment of the fastening tool is very limited. The problem is in many cases even more pronounced when protectors against kinks for the flexible lines are provided, for example, having the shape of spiral wires, since space has to also be provided for these elements. Moreover, due to the narrow spatial conditions it is frequently difficult to place a fastening tool at the screw elements. 
     BRIEF DESCRIPTION 
     The object of the present invention lies therein to provide a fastening tool, as well as a coupling part and a screw element of the initially named kind which ensures a reliable fastening of such screw elements also for narrow spatial conditions, which is also easy to handle. Furthermore, the object exists of designing a screw element in such a way that it works reliable albeit the narrow spatial conditions and can be fastened and at the same time simplifies the attachment of the fastening tool. 
     In order to satisfy this object a fastening tool, a coupling part and a screw element is provided. 
     Thus, a fastening tool for a screw element having a tool mount and an associated line is used in accordance with the invention which is characterized in that a coupling part is provided which is configured at a free end for the shape matching engagement with the tool mount and at the other end, its drive end, merges into a handle or can be coupled to a handle, and in that the coupling part has at least an inner space at its free end and at least one lateral opening for the introduction and/or removal of the line, wherein the inner space and the opening extend up to the free end and being open there. 
     The fastening tool can be brought into engagement with the tool mount via the line through the formation of the coupling part, wherein the inner space of the coupling part has to be dimensioned so large that the line has space therein, this means that the cross-section of the inner space has to be larger than the cross-section of the line. The lateral opening, on the one hand, enables a lateral or radial movement of the coupling part towards the line and subsequently an axial movement of the coupling part and/or of the fastening tool up until the free end of the coupling part arrives in the shape matching engagement with the tool mount. In this connection, the free end of the coupling part has a shape which is approximately complementary to the tool mount in such a way that a torque can be transferred via the coupling part to the screw element. For an applied fastening tool the line runs axially from the screw element through the hollow inner space of the coupling part and in a bent shape laterally through the said opening of the coupling part. 
     When the line is a flexible line, such as a hose made of plastic, which is generally the case, the flexibility of the line is sufficient in order to form the above mentioned bent shape of the line on the removal of the coupling part and further enables a limited rotational movement of the coupling part and for this reason of the screw element without damaging the line. In the event that it is a rigid line, for example, made of metal then the said opening has to be longer than the spacing from the screw element to the side of the flexible line remote from the screw element and must at least at the position of the removal of the line be configured wide enough such that a limited rotational movement of the coupling part and/or of the fastening tool for fastening of the screw element is possible. Following a limited rotational movement of the coupling part and/or of the fastening tool this can, if required, be axially removed from the tool mount of the screw element and can be turned back by a maximum possible limited amount and can be newly placed, wherein a further limited rotational movement of the screw element is possible. This method can be repeated up until the screw element has been fastened. When the available space is sufficient, the screw element can be screwed by use of fingers and can then subsequently be fastened by means of the fastening tool. In dependence on the actual circumstances, a single rotational movement of the fastening tool in a limited angular range can be sufficient to facilitate this, this means that the fastening tool does not have to be newly placed. Since the coupling part can be designed relatively thin, but with a sufficient length, the free end of the coupling part can also be used for narrow spatial conditions for the fastening of screw elements which would otherwise be inaccessible. 
     Although the tool is referred to as a fastening tool it can also be used for the release of screw elements without further ado. 
     It is particularly favorable when the fastening tool is configured as a torque wrench. 
     Hereby it is possible to fasten the corresponding screw elements to a maximum predefinable torque which in turn has the effect that the required seal of the line is ensured and that the thread is not damaged. Furthermore, the maintenance of a predefined torque ensures that, specifically for PTFE and FEP lines, the applied pressure does not become so large and that an undesired flow of the hose material occurs. Furthermore, the torque by means of which the fitting (the screw element) is tightened, is limited by means of the torque limitation, whereby the pressing together of the flange, of the support ring (if present) and possibly of an O-Ring present between the fitting and the support ring or an O-ring provided at a different position is limited, this means that an excessive pressing together is prevented. 
     Likewise it is favorable that the free end of the coupling part is provided with projections extending in an axial direction of the coupling part which engage into the longitudinal grooves of the screw element forming the tool mount in a shape matching manner. Such longitudinal grooves are preferably configured at the outer side of the screw element and are open in the direction radially outwardly. This means that the coupling part does not have to be wider than the screw element itself in the region of the screw element which favors the placing of the fastening tool also for particularly narrow spatial conditions. 
     However, it is not necessarily required that the longitudinal grooves are open radially towards the outside. Rather more, they can, for example, be replaced by axially in parallel bores, although these are not as favorable for the accessibility as the formation having longitudinal grooves which are open radially outwardly or at least means that the screw element has to be designed larger in the region of this head than for the formation with longitudinal grooves which are open radially towards the outside. 
     For such fastening tools the projections are configured free-standing which is particularly favorable in order to be able to place the fastening tool onto the screw element. Furthermore, the use of free-standing projections has the effect that the fastening tool, in particular on the use of run in inclinations with respect to the said longitudinal grooves, or one use of rounded edges of the projection can be brought into engagement with the head part of the screw in a simple manner or can be “threaded in” easily and indeed also then when the visibility conditions are not ideal due to the presence of a plurality of screw elements and for narrow spatial conditions and/or when the fastening tool is guided towards the respective screw element with a non-ideal orientation. 
     In accordance with a preferred embodiment the coupling part is configured with a socket mount for the handle at its end remote from the free end. 
     The fastening tool can be configured in such a way that the handle is realized as a screwdriver handle and as a ratchet. In both cases the handle can be configured with a function predefining or limiting a torque. 
     The opening preferably extends over a large part of the length of the coupling part and/or over the overall length of the same. This has the advantage that for a given flexibility of the line the largest possible rotational movement of the fastening tool can be achieved before it has to be newly placed. 
     In accordance with a very preferred embodiment the projections have a circular shape and are preferably formed by cylinder pins which are held with a press fit in annularly arranged bores extending in the axial direction at the associated free end by means of an adhesive or are held in a different manner in annularly arranged bores extending in the axial direction at the associated free end. 
     This construction can be realized relatively simply from a manufacturing point of view, since both the pins, produced by wire elements, and the bores, produced with small drills, can be produced in the required quality and with the required tolerance. The difficulties which are present on their manufacture can be appreciated when one uses the knowledge that the dimensions of the projections and/or of the cylinder pins for the typical screws in the analytic field have diameters of less than 1 mm and can project by approximately 6 mm over the free end of the coupling part. 
     In a further preferred embodiment a web extends between the free end facing the handle and the free end bearing the projections, wherein the angular extent of the web about the longitudinal axis is smaller than the angular extent of the opening about the longitudinal axis and preferably lies in the range of ≦120° and, in particular of ≦90°. The web is preferably maintained as small as possible. It must merely be capable of transmitting the maximum required torque reliably between the free ends of a coupling part. Due to the fact that the web is provided with an as small as possible angular extent, the opening in the region between the free end can be carried out as large as possible, whereby an as large as possible rotational range of the fastening tool can be achieved for an as small as possible hindrance through the respective line. Although the web has an as small as possible angular extent about the central longitudinal axis of the coupling part it can have a certain thickness in the radial direction which contributes to the magnitude of the transferable torque without the radial thickness itself representing a hindrance on the application of the fastening tool. 
     In a different preferred embodiment the opening has a larger extent in a region between the handle and the free end bearing the projections than in the region of this free end. 
     In a further preferred embodiment the free end remote from the handle is configured as a ring with a slot-like opening and the slot-like opening has an angular extent and/or a width which is smaller than the angular extent of the ring and/or of the circumference of the ring. Specifically the slot-like opening is dimensioned precisely so wide and/or is provided with an angular extent in such a way that the respective line can just be threaded in through the slot-like opening. 
     This, on the one hand, simplifies the attachment of the fastening tool, since it can be brought into engagement at the line remote from the head part of the screw element and can then be guided along the line up to the head part of the screw element without the danger arising that the fastening tool is brought out of engagement from the line. Thus a better guidance of the fastening tool arises. On the other hand, the small width of the slot-like opening serves the purpose that the circumference of the ring is as long as possible and for this reason that as many as possible axially extending projections can be provided at the free end face of the ring. In any case one can provide a sufficient amount of projections in this manner such that they engage in several longitudinal grooves at the circumference of the head part of the screw element and so to say cannot be removed laterally from the engagement with the head part of the screw. 
     Typically, the slot-like opening has an angular extent of approximately 90°, while the ring has an angular extent of approximately 270°. 
     Preferably, the handle extends in an axial direction from the coupling part. Hereby a relatively narrow longitudinal fastening tool is created which can be handled easily in the region of the corresponding apparatuses and connections. 
     In a preferred embodiment the coupling part is made as a plastic or a metal injection-molded part or as a plastic or a metal extruded part, preferably a part made of an aluminum alloy. Thus, a coupling part can be produced particularly cost-effectively, simply and quickly. 
     In a further preferred embodiment the coupling part at its drive end is configured with a like arrangement of radially inwardly projecting projections extending in an axial direction as at the free end, which arrangement can be coupled to a drive end of a handle and/or of a torque wrench having a complementary shape. 
     In a different preferred embodiment, the arrangement of the projections and the wall thickness of the tubular piece are selected in such a way that a hollow square shape or a hexagonal shape or a torx shape can be produced at the drive end which can be coupled to a complementary square element, hexagonal element or torx element, on the formation of the coupling part as an extruded part. 
     The invention further comprises a coupling part which is configured for the use with such a fastening tool of the previously described type. Such coupling parts cannot only be sold separate from the handle and/or from the torque limiting wrench, but different coupling parts can be sold and/or used for different screw element sizes having a handle matching all of the coupling parts. 
     Finally, a screw element having a tool mount is claimed in accordance with the invention which is configured for the cooperation with a coupling part in accordance with the invention. 
     Such a screw element in particular has a head part which is configured for the engagement of a tool, having a shaft part bearing a threaded cylinder and having a central bore which is configured for the reception of a flexible line. In accordance with the invention the head part is provided with longitudinal grooves at its outer side extending in a longitudinal direction from an end face of the head part which are e.g. semi-circular in cross-section and wherein run in regions for the longitudinal grooves are provided at the said end face which run in regions taper in the direction of the longitudinal grooves and indeed preferably taper in a conical manner, wherein the screw element is either configured as a hollow screw bolt or as a sleeve nut. 
     The provision of such longitudinal grooves is particularly favorable, since as much space as possible is created for the line and a possibly provided protection against kinks through the engagement of the fastening tool at the outer side of the head part without the diameter of the head part having to be unnecessary large. 
     In an embodiment the screw element is configured as a hollow grub screw and the longitudinal grooves are arranged in a region of the grub screw forming the head part. Such a grub screw requires no space at its head part which projects beyond the threaded bore. 
     Such screw elements can be provided with a cutout between the head part and the threaded cylinder which is, in particular configured to receive a coding ring or a similar element. Such preferably color-coded coding rings enable a simple introduction of screw elements, e.g. into a housing when the place of installation is coded with the same color. 
     Preferably, such a screw element is produced as a plastic or a metal injection-molded part and/or as a (turned) automated part. Particularly preferred embodiments of the invention are defined in the subordinate claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The invention will be described in detail in the following by means of embodiments with reference to the drawing in which is shown: 
         FIG. 1A  a side view of a coupling part in accordance with the invention having a screw element in accordance with the invention prior to the application of the coupling part; 
         FIG. 1B  the coupling part of  FIG. 1A  following the application onto the screw element; 
         FIG. 1C  an illustration corresponding to that of  FIG. 1B , but having a smaller dimension and being completed with a handle and a line; 
         FIG. 1D  a further illustration similar to that of  FIG. 1C , but turned by 90° in the clock-wise direction; 
         FIGS. 2A-2D  different views of a screw element in accordance with the invention from the side ( FIG. 2A ), in an end view ( FIG. 2B ), a section in the longitudinal direction ( FIG. 2C ) and in a perspective illustration ( FIG. 2D ); 
         FIGS. 3A-3F  different views of a coupling part in accordance with the invention from the side ( FIG. 3A ), in an end view ( FIG. 3B ), in a side view ( FIG. 3C ) in accordance with the arrow IIIC of the  FIG. 1A , as well as in two perspective illustrations ( FIGS. 3D and 3E ) and in a further end view ( FIG. 3F ); 
         FIG. 4A  a partly sectioned illustration of a screw element on the introduction into a threaded connector bore of a housing, wherein the handle has been omitted for reasons of clarity; 
         FIG. 4B  an enlarged illustration of the screw element screwed into the connection; 
         FIGS. 5A-5F  further views of a further fastening tool similar to that of  FIGS. 1A to 1D , wherein the opening of the coupling part in accordance with the invention, but is of significantly wider design; 
         FIGS. 6A + 6 B show a further screw element in accordance with the invention in a perspective view and in a top view; 
         FIGS. 7A + 7 B show a further coupling part in accordance with the invention in a perspective view and in a top view; and 
         FIG. 8A to 8C  show a further coupling part in accordance with the invention like that of  FIGS. 7A and 7B . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1A to 1D , but simultaneously also to the further Figures, the  FIGS. 1C and 1D  show a fastening tool  10  in accordance with the invention for a screw element  12 , having a tool mount  13  and having an associated line  14 . The line  14  in this example is composed of plastic and has a flange  18  provided at the end  16  facing the screw element  12  which flange is typically generated by forming and/or pressing the cutoff end of the line  14  over in a heated state. On the screwing of the screw element  12  into a connector of a housing, or into a connection piece, the flange is held between a support ring (not shown) at the end face  20  of the screw element  12  and a shoulder at an end of a threaded bore of the connector (not shown). The reference numeral  22  in  FIG. 1A  indicates a known color-coding ring which sits in a ring groove and/or at a ring shoulder of the screw element  12  at the side of the head of the screw element  12  facing the thread. 
     The reference numeral  24  represents a coupling part which at its free end  26  facing the screw element  12  ( FIGS. 1B and 1C ) is configured for the shape matching engagement with a tool mount  13  of the screw element  12 . At its other end  30  the coupling part  24  has a mount, in the present example in the shape of a square opening  31  in cross-section, for a handle  32  which can be inserted into the end  30  of the coupling part with a corresponding complementary shape, for example, a common square shape  34 . Thus the coupling part in this example can be coupled to the handle  32 . Otherwise, the corresponding “end” of the coupling part  24  can merge into the handle  32 , this means that it can be fixedly coupled thereto. 
     In other words, the coupling part is configured with a plug mount for the handle  32  at its end  30  remote from the free end  26  and the handle  32  can be configured as a screwdriver handle or as a ratchet. In both cases the handle can be configured with an installed function predefining or limiting the torque. 
     The coupling part  24  further comprises at least one inner space  36  at its free end  26  and/or in the region of its free end  26  and at least one lateral opening  38  for the introduction and/or removal of the line  14 , wherein the inner space  36  and the opening  38  extend up to the free end  26  and are open there. 
     The handle  32  is preferably configured as a torque wrench. Such handles  32  having the shown shape of a screwdriver handle are commercially available from the company Wika. Instead of this, a common torque wrench having a square end can be used with the coupling part  24  in accordance with the invention. 
     The free end  26  of the coupling part  24  is provided with free-standing projections  40  which extend in an axial direction of the coupling part and which engage the tool mount  13  of the screw element  12  formed by longitudinal grooves  42  and/or which engage into the screw head of the screw element in a shape matching manner. The longitudinal grooves  42  are configured at the outer side of the screw element  12  and are open in a radially outward direction. At their ends facing the coupling part  24  the longitudinal grooves  42  have conical run in regions which enable the introduction of the projections  40  into the coupling part  24 . 
     The projections  40  have a cylindrical shape (see  FIG. 6 ) so that, on their introduction, they can be guided particularly efficiently into the longitudinal grooves  42  of the screw element  12  through the conical shape of the run in regions  44  of the screw element  12 . Thereby it is ensured that the projections  40  can find their own way into the longitudinal grooves  42  in such a way that the coupling part  24  can be brought into engagement with the screw element  12  without too much demand in effort. Thus, a relatively simple fastening and/or loosening of the screw elements is ensured by means of the coupling part  24 . This is particularly advantageous when the screw element  12  has to be installed in relatively small apparatuses where little space is present. 
     It is in particular evident from  FIG. 1C  that the opening  38  extends over a large part of the length of the coupling part  24 , i.e. nearly over the overall length of the same.  FIG. 1D  shows a further illustration similar to that of  FIG. 1C , where the coupling part is, however, rotated about 90° in the clock-wise direction. 
     On use of the fastening tool the handle  32  and the coupling part are normally connected first, this means that the square of the handle  32  is plugged into the plug mount  31  of the coupling part  24 . Following this, the coupling part  24  is moved sideways over the line  14  in such a way that this approximately takes on a position in accordance with  FIG. 1A . Only then is the fastening tool moved axially with respect to the central longitudinal axis of the screw element  12  and the line  14  is moved into the region of the screw element  12  in such a way that the projections  40  engage with the longitudinal grooves of the screw element  12  (cf.  FIG. 1C ). Following this, a torque can be exerted onto the handle  32  and onto the screw element  12  via the coupling part  24 . However, the coupling part  24  can first be placed onto the line  14  and then can be brought into engagement with the screw element  12 , before the handle  32  is plugged into the coupling part  24 . 
     The inner space  36  of the coupling part  24  is dimensioned so large that the line  14  has space therein, this means that the cross-section of the inner space  36  must be larger than the cross-section of the line  14  and the diameter of the cylindrical inner space  36  is preferably at least twice or three times as large as the outer diameter of the line  14 . The lateral opening  38 , on the one hand, enables a lateral or radial movement of the coupling part  24  towards the line  14  and subsequently an axial movement of the coupling part  24  and/or of the fastening tool  12  up until the free end  26  of the coupling part  24  arrives in the shape matching engagement with the tool mount  13  of the screw element  12 . In this respect the free end  26  of the coupling part and/or the projections  40  provided there have a shape which is approximately complementary to the tool mounts  13  in such a way that a torque can be transmitted from the handle  32  to the screw element  14  via the coupling part  24 . 
       FIG. 3F  shows a further end view of a coupling part  24  in accordance with  FIGS. 3A to 3E . In this example the circular cross-section of the circular projections  40  can be seen. The projections  40  are preferably formed by cylinder pins which are held with a press fit in annularly arranged bores extending in the axial direction at the associated free end by means of an adhesive or are held in a different manner in annularly arranged bores extending in the axial direction at the associated free end. This construction can be realized relatively simply from a manufacturing point of view, since both the pins, produced by wire elements, and the bores, produced with small drills, can be produced in the required quality and with the required tolerances. 
     In the  FIG. 4A  a partly sectioned illustration of a screw element  12  is shown on the introduction into a threaded bore connector  48  of a housing  50 , wherein the handle  32  has been omitted in the illustration. The  FIG. 4B  shows an enlarged illustration of the screw element  12  screwed into the connector  48 . The  FIG. 4B  further shows how the end face  20  of a screw element presses against a support ring  52  and via this onto the flange  18  of the line  14  and presses the flange to the base  54  of the threaded bore  48  for a screwed in screw element  12 . 
     The  FIG. 5A to 5F  show an alternative coupling part  24  in which the opening  36  has a considerable width which extends over approximately 270° of the circumference of the coupling part  24  (wherein this angular statement should be understood purely by way of example and not in a limiting manner). In accordance with this a relatively narrow web  25  remains which connects the free drive end  26  to the handle side end  30 . Thus, the fastening tool can be turned over an extended angular range in order to bring about a corresponding large angular dependent fastening movement of the screw element  12 . It should finally be noted that the opening  36  can have a different shape, for example a T-shape, wherein the opening can, for example, be narrower in the region of the drive end  26  and wider in the region of the handle side end  30 . 
     The width of the web  25  is selected in such a way that the transfer of a torque to the screw element  12  is ensured via the coupling part  24 . Typically, torques in the ranges of 0.05 to 2 Nm, in particular of 0.1 to 1 Nm are used for plastic screws  12  in dependence on the size of the screw element. For metal screws  12 , a torque of approximately 0.1 to 120 Nm, preferably between 2 and 50 Nm can be transmitted to the screw element by means of the coupling element  24  in dependence on the metal and the size. 
       FIGS. 6A and 6B  show a further screw element  12  in a perspective view and in a top view. In this embodiment the screw element  12  is configured as a hollow grub screw and the longitudinal grooves  42  are arranged in a region of the grub screw  12  forming the head part  58 . Such a grub screw  12  does not require any space at its head part  58  which projects beyond the threaded bore. The screw element  12  has a head part  58  which can be configured for the engagement of a tool (see e.g.  FIG. 1 ), a shaft part bearing a threaded cylinder  60  and a central bore which is configured for the reception of a flexible line  14 . 
     The longitudinal grooves  42  which are provided at the outer side of the head part  58  are semi-circular in cross-section and run in regions  44  for the longitudinal grooves  42  are provided at the end face remote from the end of the threaded cylinder  60 , said run in regions  44  tapering in a direction of the longitudinal grooves  42  and indeed preferably taper conically. This provision of the longitudinal grooves  42  in the head part  58  enables the engagement of the fastening tool  24  at the outer side of the head part  58  without the diameter of the head part having to be made unnecessarily large. 
     A cutout  46  is arranged between the head part  58  and the threaded cylinder  60  of the screw element  12  which is, in particular configured to receive a coding ring  22  or a like element. Such preferably color-coded coding rings enable a simple introduction of screw elements  12 , e.g. into a housing, when the place of installation is coded with the same color (see e.g.  FIGS. 4A and 4B ). Such a screw element  12  is preferably made as a plastic or a metal injection-molded part and/or is produced as a (turned) automated part. 
       FIGS. 7A and 7B  show a further view of a coupling part  24 . In particular the  FIG. 7A  shows a perspective view. Also in this example a web  25  extends between the drive end  30  and the free end  26  bearing the projections  40 . The angular extent of the web  25  about the longitudinal axis is smaller than the angular extent of the opening  38  about the longitudinal axis. 
     The coupling part  24  of the  FIGS. 7A and 7B  has been manufactured from an extruded part, preferably of an aluminum alloy. Such extruded parts can be produced very simply, quickly and cost-effectively. Thereafter, they are cut to the desired length and are provided with their opening  38 . A slot-like opening  38  is configured in the ring  56  at the free end  26  remote from the handle, which slot-like opening has an angular extent and/or a width which is smaller than the angular extent of the ring  56  and/or of the circumference of the ring  56 . Specifically, the slot-like opening  38  is dimensioned at least so wide in all embodiments and/or having an angular extent such that the respective line  14  can just be threaded in through the slot-like opening  38 . Thus, a coupling part  24  can be produced particularly cost-effectively, simply and quickly. 
     As can be seen in the  FIG. 7B  projections  40  extend in an axial direction radially inwardly which can be coupled to a drive end  30  of a handle and/or of a torque wrench having a complementary shape  31 . In the present example the arrangement of the projections  40  and the wall thickness of the tubular piece are selected in such a way that a hollow square shape  31  (see  FIG. 7A ) can be produced at the drive end  30  which can be coupled to a complementary square element. Also a different shape can be produced at and/or in the drive end  30  including an outer square or a different suitable drive shape. 
     The  FIGS. 8A to 8C  show a coupling part similar to that of  FIGS. 7A and 7B . The central difference is to be considered therein that the ring section  56  at the free end  26  has a larger angular extent, this means a larger circumferential length and thus better engages around the screw head. A further difference lies in the width of the web  25 . In this example it is evident that more material has been cut away from the sidewall and/or cut out of the sidewall or has been omitted such that the web  25  has a significantly smaller angular extent than the cut away or left away region. 
     Also in this example the coupling part  24  generally has the shape of a tubular piece which in a side view has an extended in U-shape. 
     The screw elements shown in this connection can be common screw elements  12  having the sizes of e.g. M4, M5, M6, M7, M8, M9 or M10 or can also be produced in corresponding imperial or customary units. The screw elements  12  can, however, also have specifically manufactured sizes which are adapted to a respective threaded bore connector  48 .