Abstract:
A joint lock comprises a lock body and a joint bar hoop, wherein the lock body accommodates a lock cylinder and a latch which is selectably movable by the lock cylinder from a locked position into a release position and wherein the joint bar hoop comprises a plurality of joint bars pivotally linked to one another, wherein a first end of the joint bar hoop has an elongate closing bar which can be introduced into an introduction opening of the lock body and which can be locked in the lock body by means of the latch. The joint lock is characterized in that the lock body furthermore accommodates a preloading device which preloads the latch into the locking position, with the latch being temporarily movable against the preloading from the locking position into the release position by introduction of the locking bar into the lock body, with the preloading device being adapted to move the latch back into the locking position again when the locking bar is completely introduced into the lock body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of German Patent Application 102013210475.8 filed on Jun. 5, 2013. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a joint lock having a lock body and a joint bar hoop, wherein the lock body accommodates a lock cylinder and a latch which is selectably movable by the lock cylinder from a locked position into a release position and wherein the joint bar hoop comprises a plurality of joint bars pivotally connected to one another, wherein a first end of the joint bar hoop has an elongate locking bar which can be introduced into an introduction opening of the lock body and which can be locked in the lock body by means of the latch. 
       BACKGROUND OF THE INVENTION 
       [0003]    Such a joint lock serves, for example, for the securing of a two-wheeler to a bicycle stand, to a lamppost or the like. For this purpose, the joint bars of the joint bar hoop which are pivotally connected to one another behind one another or in a row are folded apart and the locking bar, which forms the free end of the joint bar hoop, is locked to the lock body in order hereby to form a closed loop. This closed loop can, for example, engage around a frame section of the two-wheeler and the bicycle stand, lamppost or the like, or the joint bar hoop only surrounds a rim of the two-wheeler to prevent unauthorized persons from riding away. 
         [0004]    The joint bars can be folded together to form a compact arrangement by the authorized user for the transport of the joint lock, with it in particular being possible also to lock the locking bar in the lock body in the folded together state of the joint bar hoop, with the joint bar hoop maintaining the folded together shape. To bring the joint bar hoop into the folded together shape, it is known to pivot the joint bars in the manner of a folding yardstick and hereby to bring it into a parallel alignment. 
         [0005]    A disadvantage of the known joint locks comprises the fact that the latch has to be moved into the release position by means of the lock cylinder and the matching key in order to introduce the locking bar into the introduction opening of the lock body. The latch subsequently has to be brought into the locking position by means of the key to lock the locking bar in the lock body. Both the introduction of the locking bar into the lock body and the locking of the locking bar in the lock body thus require a manual operation. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of the invention to provide a joint lock which is simple to handle. 
         [0007]    This object is satisfied by a joint lock having the features of claim  1  and in particular in that the lock body furthermore accommodates a preloading device which preloads the latch into the locking position, with the latch being temporarily movable against the preloading from the locking position into the release position by introduction of the locking bar into the lock body, with the preloading device being adapted to move the latch back into the locking position again when the locking bar is completely introduced into the lock body. 
         [0008]    The latch is thus automatically briefly moved from the locking position into the release position simply by the introduction of the locking bar into the lock body, whereby the locking bar can be introduced into the lock body without any additional movement of the lock cylinder. The introduction of the locking bar in this respect takes place against a preloading of the latch which is produced by means of the preloading device. As soon as a section of the locking bar provided for introduction into the lock body is introduced into the lock body, i.e. when the locking bar is completely introduced into the lock body, the latch is urged back into the locking position by the preload, whereby the locking bar is locked in the lock body. A removal of the introduced locking bar from the lock body is not possible in the locking position. The locking bar can only be removed from the lock body again when the latch is moved by the lock cylinder from the locking position into the release position. 
         [0009]    In an advantageous manner, the joint lock in accordance with the invention thus allows an automatic function for locking the introduced locking bar without an actuation of the lock cylinder. The handling of the joint lock in accordance with the invention on locking is thus simple and uncomplicated since only the locking bar has to be introduced into the lock body and is automatically locked there. 
         [0010]    Advantageous embodiments of the invention are described in the description, in the dependent claims and in the drawings. 
         [0011]    In accordance with a first advantageous embodiment, the locking bar has a locking section at a free end which is in operational engagement with the latch in the locking position of the latch to lock the locking bar in the lock body. In this respect, that end of the locking bar is defined as the free end which can be introduced into the lock body. A second end of the locking bar, which is disposed opposite the free end, is pivotally connected to a joint bar of the joint bar hoop, in contrast. The locking section can in particular be in operational engagement with the latch when the locking bar is completely introduced into the lock body. 
         [0012]    The locking section of the locking bar is preferably formed by an elevated securing portion, i.e. by an elevated portion with respect to the surface of the locking bar. The elevated securing portion is preferably provided at a broad side of the typically flat locking bar. The latch can be arranged in the locking position such that it is in operational engagement with the elevated securing portion to prevent a pulling of the locking bar out of the lock body in that the latch blocks the movement path of the elevated securing portion and/or cants with the elevated securing portion. 
         [0013]    In accordance with a further advantageous embodiment, the preloading device is fastened to the lock cylinder and to the latch. This means that the preloading device engages both at the lock cylinder and at the latch to load the lock cylinder and the latch with respect to one another, whereby the preloading device, the lock cylinder and the latch can form an independent unit. The preloading device can in this respect be configured as a spring, for example. 
         [0014]    The latch is preferably configured as a rotating latch which is rotatably supported at a jacket surface of the lock cylinder. The rotating latch can contact an outer jacket surface of the lock cylinder, in particular a cylindrical jacket surface of a cylinder housing, whereby the lock cylinder forms a support surface for the rotating latch. The rotating latch can in this respect have the shape of a sector of a hollow cylinder, with the inner surface of the hollow cylinder contacting the cylindrical outer surface of the lock cylinder. A simple support of the rotating latch is possible in this manner. In addition, the use of a rotating latch considerably increases security against an unauthorized opening of the joint lock since the latch could, for example, be briefly moved out of the locking position into the release position by a hammer blow onto the lock body on a use of a linearly displaceable latch. The triggering of a rotational movement to bring the rotating latch into the release position is, however, not possible by a hammer blow onto the lock body. The named preloading device can be configured as a torsion spring in this embodiment. 
         [0015]    In accordance with a further advantageous embodiment, the axis of rotation of the rotating latch coincides with or extends in parallel with an axis of rotation of the lock cylinder. The rotating latch and the lock cylinder can therefore be arranged coaxially or almost coaxially. 
         [0016]    The rotating latch advantageously comprises a jacket surface having a cut-out, with the cut-out releasing a movement path of the locking bar in the release position of the rotating latch. In the release position, the rotating latch can be positioned such that the cut-out lies in the movement path of the locking bar and in particular at least releases the named elevated securing portion. If the cut-out is arranged in the movement path of the locking bar, the locking bar can be introduced into or pulled out of the lock body. In the locking position, in contrast, the cut-out of the rotating latch is moved out of the movement path of the locking bar, whereby the movement path of the locking bar or of the named elevated securing portion is blocked and the introduced locking bar is locked in the lock body. 
         [0017]    In accordance with a further advantageous embodiment, the aforesaid cut-out extends in a tangential direction along the jacket surface of the rotating latch with respect to the axis of rotation of the rotating latch. The rotating latch can substantially have the shape of a hollow cylinder or of a sector of a hollow cylinder, with the cut-out extending in the peripheral direction of the jacket surface of the rotating latch and extending along a certain angular region of the jacket surface. Consequently, the cut-out or a region of the jacket surface of the rotating latch without a cut-out can selectively be brought into the movement path of the locking bar by a rotation of the rotating latch. 
         [0018]    The lock cylinder advantageously has a cylinder housing and a cylinder core which is rotatably supported in the cylinder housing and which is coupled to the rotating latch drive operationally, but with rotational clearance. The cylinder core can selectively be rotationally moved by means of a key associated with the lock cylinder. The rotating latch can be rotated about its axis of rotation by a rotational movement of the cylinder core, which can be transmitted to the rotating latch, to release the movement path of the locking bar or of an elevated securing portion provided thereat, for example. In addition, due to the rotational clearance provided between the cylinder core and the rotating latch, the rotating latch can be temporarily rotated into the release position on the introduction of the locking bar into the lock body, without a rotational movement of the cylinder core being necessary. Subsequently, due to the preload, a return of the rotational latch from the release position into the locking position can take place without a rotational movement of the cylinder core being necessary. 
         [0019]    In accordance with an advantageous embodiment, the cylinder core has a drive prolongation whose cross-section is partly formed by a segment of a circle and partly by an abutment edge, with the drive prolongation engaging into a coupling opening of the rotating latch, and with the cross-section of the coupling opening being partly formed by a segment of a circle and partly by a first abutment edge and partly by a second abutment edge which is adjacent to the first abutment edge and includes an angle with it differing from 0° and 180°. A rotational movement of the cylinder core can be transmitted to the rotating latch by means of the drive prolongation to rotate the rotating latch and, for example, to vary the position of the cut-out of the rotating latch. The drive prolongation is in this respect an extension of the cylinder core which is defined by a segment of a circle bounded by a secant. The drive prolongation is likewise set into rotation by a rotation of the cylinder core and transmits its rotational movement to the first abutment edge of the rotating latch, for example. The coupling opening can be formed by a segment of a circle into which a triangular abutment projects, with the first abutment edge being able to be formed by a first secant section and the second abutment edge being able to be formed by a second secant section, the two secant sections including an angle with one another. The aforesaid rotational clearance between the cylinder core and the rotating latch can be defined by this angle, namely in that either the named first abutment edge or the named second abutment edge of the coupling opening of the rotating latch contacts the named abutment edge of the drive prolongation. 
         [0020]    The lock body, in particular the internal housing explained in the following, can furthermore comprise an abutment which bounds a rotational movement of the cylinder core and/or of the rotating latch to prevent an overrotation of the cylinder core in the cylinder housing or an overrotation of the rotating latch in at least one rotational direction. 
         [0021]    The locking bar can advantageously be introduced along its longitudinal axis into the introduction opening of the lock body, with an axis of rotation of the lock cylinder being oriented perpendicular to a plane which is spanned by the longitudinal axis of the locking bar (i.e. the direction of introduction of the locking bar) and the joint axis of the locking bar, when the locking bar is introduced into the lock body. A rotation of the rotating latch about its axis of rotation can thus be effected on the introduction of the locking bar into the lock body. This can in turn effect the displacement of the cut-out of the rotating latch into the movement path of the locking bar, whereby the locking bar can be completely introduced into the lock body. 
         [0022]    The aforesaid plane in particular corresponds to the plane of extent of the joint bars and of the locking bar when the joint bar hoop is folded together in the manner of a yardstick and the joint bars and the locking bar lie next to one another in parallel with one another. An alignment of the lock cylinder in which the direction of introduction of the key extends perpendicular to the named plane is also advantageous in the following manner: When not in use, the joint lock can be stored in an associated lock bag during transport which is typically mounted at the frame tube of a bicycle such that the longitudinal axes of the joint bars extend in parallel with the longitudinal axis of the frame tube and the broad side of the formed joint bar package faces the frame tube (cf., for example, the lock bag shown in DE 20 2005 013 390 U1). If the introduction opening of the key at the lock body in such an arrangement of the joint lock is aligned perpendicular to the aforesaid plane, the key can remain inserted in the lock cylinder during the transport of the joint lock without the key projecting into the movement region of the cyclist and thereby being able to disturb the cyclist in his movement processes. 
         [0023]    Alternatively, the locking bar can be laterally pivoted into the introduction opening of the lock body, with an axis of rotation of the lock cylinder being aligned in parallel with the longitudinal axis of the locking bar when the locking bar is introduced into the lock body. The movement path of the locking bar on a lateral introduction into the lock body in the region of the lock body can therefore be approximately perpendicular to a plane which is defined by the axis of rotation of the rotating latch and by the longitudinal axis of the locking bar in the completely introduced state. On a pivoting inward of the locking bar, a rotation of the rotating latch can be effected which allows the complete introduction of the locking bar into the lock body. 
         [0024]    Alternatively to the use of a rotating latch, the latch can also be configured as a snap-in latch which projects into the movement path of the locking bar. The snap-in latch can in this respect be temporarily urged back from an end face of the locking bar and can engage into a recess of the locking bar or engage behind an elevated securing portion of the locking bar after the complete introduction of the locking bar into the lock body to lock the locking bar in the lock body. To urge the snap-in latch back, the snap-in latch and/or the end face of the locking bar can comprise a sloped surface by which the snap-in latch is urged back on an introduction of the locking bar into the lock body. In this embodiment, an elevated securing portion at the locking bar is not absolutely necessary since an engagement of the latch can—as explained—be provided in a recess of the locking bar, for example. 
         [0025]    It is particularly advantageous if the locking bar has at least one elevated protection portion which is provided—viewed along the longitudinal axis of the locking bar—between the introduction opening of the lock body and the latch when the locking bar is completely introduced into the lock body. Such an elevated protection portion serves for the protection against a manipulation of the latch from the outside, for example when an attempt is made to move the latch in the direction of its release position by means of a flat tool through the introduction opening of the lock body. In other words, the elevated protection portion of the locking bar prevents an access to the operational region between the latch and the locking bar. The elevated protection portion can be configured as a raised portion with respect to a broad side of the locking bar typically of a flat design. The elevated protection portion can in particular be provided at that side of the locking bar which faces the latch within the lock body. The elevated protection portion can be provided, for example, between the introduction opening of the lock body and the named elevated securing portion of the locking bar when the locking bar is completely introduced into the lock body. 
         [0026]    A particularly inexpensive manufacture of the joint lock can in particular be achieved in that the lock body has a single-part internal housing with two support openings at two mutually oppositely disposed sides, with the lock cylinder having a cylinder housing and a cylinder core rotatably supported in the cylinder housing (in particular the already named cylinder housing and cylinder core), with the lock cylinder being captured between the two mutually oppositely disposed sides of the internal housing and with the cylinder core being rotatably supported in the two support openings of the internal housing. The single-part internal housing can in this respect be produced as a stamped bent part from metal. 
         [0027]    In accordance with an advantageous further development, the named single-part internal housing has at least one bent-over holding tongue which fixes the cylinder housing against a rotation. The cylinder housing can hereby be rigidly fixed in the internal housing in a particularly simple manner. Two such holding tongues are preferably provided which engage at two different sides of a flange section of the cylinder housing. 
         [0028]    It is furthermore of advantage if the lock body has a sleeve which peripherally surrounds the named single-part internal housing in order additionally to stabilize it. The sleeve is preferably produced from metal and is completely open at one end to be able to pull the sleeve onto the internal housing. The fixing of the sleeve to the internal housing can take place by shape matching, for example by a spot deformation and a corresponding engaging behind the internal housing at a plurality of points along the periphery. 
         [0029]    In accordance with a further advantageous embodiment, a second end of the joint bar hoop is permanently fastened to the lock body. In this manner, a losing or an unintentional falling down of the joint bar hoop can be prevented. The joint bar hoop can in particular be rotatably fastened to the lock body, whereby the lock body is pivotable with respect to the joint bar hoop. The rotatable fastening of the second end of the joint bar hoop to the lock body can be provided in the region of the longitudinal axis of the lock body, i.e. the axis of rotation coincides with the longitudinal axis of the lock body or is only slightly spaced apart herefrom to maximize the length of the closed loop. 
         [0030]    In accordance with a further advantageous embodiment, the plastic jacket of the first end of the joint bar hoop has a different color than that of the second end of the joint bar hoop which is pivotally connected to the lock body. Provided that the lock body and the second end of the joint bar hoop are of the same color, the first end of the joint bar hoop, which can be distinguished by color, already visually indicates to the user which end of the joint bar hoop is releasable from the lock body. The respective plastic jacket of the locking bar and of all the joint bars with the exception of the joint bar corresponding to the second end of the joint bar hoop can in particular be of a first color, while the joint bar corresponding to the second end of the joint bar hoop and the lock body can be of a second color different herefrom. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The invention will be explained in the following only by way of example with reference to the drawings. Elements which are the same or of the same kind are marked by the same reference numerals. 
           [0032]    There are shown: 
           [0033]      FIG. 1  a joint lock in accordance with the invention in (a) a perspective view obliquely from above; and in (b) a view form above with a removed external housing; 
           [0034]      FIG. 2  the region of the lock body of the joint lock of  FIG. 1  in (a) a view from above and in (b) a view from below; 
           [0035]      FIG. 3  the region of the lock body of  FIG. 2  with an exposed lock cylinder and a rotating latch in (a) a view from above and in (b) a view from below; 
           [0036]      FIG. 4  the region of the lock body of  FIG. 3  in (a) a perspective view from the front and in (b) a perspective side view; 
           [0037]      FIG. 5  a perspective representation of the lock cylinder with a rotating latch obliquely from above; and 
           [0038]      FIG. 6  a perspective representation of the lock cylinder with a rotating latch from below. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0039]    The joint lock  10  shown in  FIG. 1   a  comprises a lock body  12  as well as a joint bar hoop  14  fastened thereto. The joint bar hoop  14  can be folded together to form a compact unit and can in this state preferably also be locked at the lock body  12 . In the unlocked state of the joint lock  10 , the joint bar hoop  14  can be folded apart to form a loop in a known manner and hereby to lock a two-wheeler or to secure it to another object (e.g. a bicycle stand). 
         [0040]    The joint bar hoop  14  in detail has a plurality of joint bars  16  of which one is formed as a locking bar  18 . The joint bars  16  and the locking bar  18  are each flat and preferably comprise steel which is surrounded by a plastic jacket  20  to avoid damage to the two-wheeler to be locked. The joint bars  16  and the locking bar  18  are pivotally connected to one another in series by a respective rivet  22  such that the joint axes extend in parallel with or coaxial to one another and the joint bar hoop  14  can be folded together in the manner of a yardstick. In the folded-together state of the joint bar hoop  14 , the longitudinal axes of the joint bars  16  and of the locking bar  18  extend in a plane in parallel with one another. A first end  24  of the joint bar hoop  14  is formed by the free end of the locking bar  18  which serves as a locking section as will be explained in the following. A second end  26  of the joint bar hoop  14  is pivotally connected to the lock body  14 . 
         [0041]    The lock body  12  comprises a substantially parallelepiped-shaped external housing  28  which is formed from plastic. The second end  26  of the joint bar hoop  14  is flush with a side wall of the external housing  28 . At an upper side of the external housing  28 , a key opening  30  is accessible through which a key  32  can be introduced into the lock body  12 . The direction of introduction of the key  32  extends perpendicular to a plane defined by the joint bar hoop  14  in the folded together and locked state. 
         [0042]    In a region which is disposed opposite the second end  26  of the joint bar hoop  14 , the lock body  12  furthermore comprises an introduction opening  34  through which the locking bar  18  can be introduced along its longitudinal axis into the lock body  12 . When the locking body  18  is introduced into the introduction opening  34 , the locking body  18  is surrounded substantially in a shape matched manner by the bounding of the introduction opening  34  of the external housing  28 . 
         [0043]      FIG. 1   b  shows the joint lock  10  without the external housing  28 . A sleeve  29  of deep drawn sheet metal can be recognized in which the key opening  30  and the introduction opening  34  continue and whose function will be explained in the following. 
         [0044]    In  FIGS. 2   a  and  23   b , the lock body  12  is shown with an introduced locking bar  18 , but without the external housing  28  and without the sleeve  29 . The external housing  28 , not shown here, is latched at latch projections  36  and accommodates an internal housing in the form of a lock body reinforcement  38  which is produced from steel sheet metal. The lock body reinforcement  38  forms a cage-like structure and in this respect in particular prevents an access into the interior of the lock body  12  from above (cf.  FIG. 2   a ) and from below (cf.  FIG. 2   b ). The lock body reinforcement  38  is additionally connected in a force-transmitting manner to the rivet  22  of the second end  26  of the joint bar hoop  14  and thus fastens the joint bar hoop  16  rotatably at the lock body  12 . 
         [0045]    The lock body reinforcement  38  is furthermore formed as a guide of the locking bar  18  and in the completely introduced state of the locking bar  18  prevents a lateral movement, an upward or a downward movement as well as a rotation of the locking bar  18 . 
         [0046]    The key opening  30  is continued in the lock body reinforcement  38 , with the key opening  30  being of circular shape and having a diameter which is matched to the diameter of an upper end of a lock cylinder  40 . The upper end of a rotatable cylinder core  50  of the lock cylinder  40  in this respect projects in a shape-matched manner into the key opening  30  of the lock body reinforcement  38 , whereby the lock body reinforcement  38  provides a support for the lock cylinder  40  ( FIG. 2   a ). 
         [0047]    At the lower side ( FIG. 2   b ), a drive prolongation  42  of the cylinder core  50  projects into a support opening  44  of the lock body reinforcement  38 . The drive prolongation  42  comprises a cross-section which is formed by a segment of a circle bounded by a secant, with the secant defining an abutment edge  46 . The bounding of the support opening  44  of the lock body reinforcement  38  comprises a triangular abutment  48  which bounds a rotational movement of the drive prolongation  42  of the cylinder core  50  by cooperation with the named abutment edge  46 . In this manner, a rotational actuation of the lock cylinder  40  is also bounded by means of the key  32 . 
         [0048]    The drive prolongation  42  is likewise indirectly supported by the lock body reinforcement  38  so that the lock cylinder  40  is supported both at its upper end and at its lower end by the lock body reinforcement  38 . 
         [0049]    The lock body  12  without the lock body reinforcement  38  is shown in  FIGS. 3   a ,  3   b ,  4   a  and  4   b . The lock cylinder  40 , which comprises the rotatable cylinder core  50  as well as a fixed-position cylinder housing  52 , is arranged within the lock body reinforcement  38  (not shown). The cylinder housing  52  has a hollow cylindrical part in which the cylinder core  50  is supported and has a flange section  53  which projects radially herefrom and in which tumblers are arranged which are urged back by the key  32  in order selectively to be able to unlock the lock cylinder  40  and to be able to rotate the cylinder core  50 . 
         [0050]    An axis of rotation of the cylinder core  50  of the lock cylinder  40  extends perpendicular to a plane which is spanned by the longitudinal axis of the locking bar  18  and by the joint axis of the locking bar  18  and which is defined by the associated rivet  22 . This plane corresponds in  FIGS. 2   a ,  2   b ,  3   a  and  3   b  to the plane of the paper and thus to the plane of extent of the joint bars  16  and of the closing bar  18  in the shown folded together state of the joint lock  10 . A substantially hollow cylindrical rotating latch  54  is arranged coaxially to the axis of rotation of the lock cylinder  40  and is movably supported at an outer jacket surface  55  of the hollow cylindrical part of the cylinder housing  52 . The rotating latch  54  is rotatable about the axis of rotation of the lock cylinder  40  relative to the cylinder housing  52 . The rotating latch  54  surrounds a part of the periphery of the lock cylinder  40 , with the rotating latch  54  comprising a peripheral clearance through which the flange section  53  of the cylinder housing  52  projects. The peripheral clearance  56  is in this respect larger than the thickness of the flange section  53 , whereby the rotating latch  54  has a specific rotational clearance with respect to the locking cylinder  40 . 
         [0051]    At a lower side of the rotating latch  54  the rotating latch comprises a coupling region  58  ( FIG. 3   b ) which forms a base of the rotating latch  54  on which the lock cylinder  40  is seated. A coupling opening  60  is provided centrally in the coupling region  58 ; the drive prolongation  42  of the lock cylinder  40  projects into said coupling opening which is surrounded by a ring section  61 . To transmit a rotation of the cylinder core  50  and thus of the drive prolongation  42  to the rotating latch  54 , the coupling opening  60  comprises a first abutment edge  62  which is formed by a first secant and which contacts the abutment edge  46  of the cylinder core  50  in the shown closing position of the rotating latch  54 . The coupling opening  60  furthermore comprises a second abutment edge  64  formed by a second secant. The first and second abutment edges  62 ,  64  include an angle of approximately 135° with one another, whereby a rotational clearance of approximately 45° results between the cylinder core  50  and the rotating latch  54 . The configuration of the coupling region  58  of the rotating latch  54  is shown even more clearly in the lower view in accordance with  FIG. 6 . 
         [0052]    A spring  66  which runs around the locking cylinder  40  in the locking position of the rotating latch  54  is clamped between the cylinder housing  52  of the lock cylinder  40  and the rotating latch  54 , with approximately 270° being swept over by the spring. Two cylindrical prolongations  68  are provided at the rotating latch  54 ; they project out of the end face at an upper end face of the rotating latch  54  and the spring  55  is threaded through them to establish a force-transmitting connection of the spring  66  to the rotating latch  54 . 
         [0053]    The spring clamps the rotating latch  54  with respect to the cylinder housing  52  such that the rotating latch  54  is urged counter-clockwise in the view of  FIG. 3   a . The rotating latch  54  is pressed by the force of the spring  66  toward a side of the flange section  53  of the cylinder housing at the left (in  FIG. 3   a ), with the cylinder housing  52  being immovably fastened in the lock body  12 . This is the locking position of the rotating latch  54 . 
         [0054]    An outer jacket surface  69  of the rotating latch comprises a passage in the form of a cut-out  70  which is shown in detail in  FIG. 5 . The cut-out  70  comprises a flat region  72  in which the depth of the cut-out  70 , viewed in the peripheral direction of the rotating latch  54 , increases less than in a steep region  74 . The flat region  72  of the cut-out  70  lies—viewed in the direction of introduction of the locking bar  18 —in front of the steep region  74 . 
         [0055]    The depth of the cut-out  70  is matched to the height of an elevated securing portion  76  ( FIGS. 3   a ,  3   b ,  4   a  and  4   b ) of the locking bar  18  which is arranged at a broad side of the flat locking bar  18 . The elevated securing portion  76  has the shape of a cylinder sector and is arranged in the region of the first end  24  of the locking bar  18  such that it faces in the direction of the rotating latch  54  in the introduced state of the locking bar  18 . The elevated securing portion  76  is formed from steel and is not surrounded by the plastic jacket  20 . An elevated protection portion  78  which has the shape of a spherical segment is furthermore provided at the first end  24  of the locking bar  18  in the direction of the rivet  22  of the locking bar  18  adjacent to the elevated securing portion  76 . 
         [0056]    Finally, the fixing of the lock cylinder  40  in the lock body  12  will be explained in more detail. The cylinder core  50  engages in shape-matched manner into the key opening  30  of the lock body reinforcement  38  at the upper side of the lock cylinder  40 . The drive prolongation  42  of the cylinder core  50  engages into the support opening  44  of the lock body reinforcement  38  at the lower side of the lock cylinder  40 , with the cylinder core  50  being indirectly supported in the support opening  44  via the ring section  61  of the coupling region  58  of the rotating latch  54 . The lock cylinder  40  is hereby captured between two mutually oppositely disposed wall sections of the single-part lock body reinforcement  38 , i.e. captured in the axial direction and in the radial direction (with respect to the axis of rotation of the lock cylinder  40 ). In addition, the cylinder housing  52  is rotationally fixedly held in the lock body reinforcement  38  in that two inwardly bent over holding tongues  39  of the lock body reinforcement  38  (cf.  FIG. 2   a ) support the flange section  53  of the cylinder housing  52  (cf.  FIG. 3   a ) at both sides. A respective blocking of the cylinder housing  52  in both directions of rotation is hereby effected. 
         [0057]    The cylinder housing  52  of the lock cylinder  40  is thus fixed in a stationary position in the lock body reinforcement  38  in a very simple manner and without separate fastening elements, with the lock body reinforcement  38  being able to be designed as a single stamped bent part. The sleeve  29  shown in  FIG. 1   b  in this respect serves for the additional stabilization of the lock body reinforcement  38  and for the protection of the lock cylinder  40  in that the sleeve  29  surrounds the lock body reinforcement  38  peripherally as well as at the side remote from the rivet  22 . The sleeve  29  thus forms an outer box for the lock body reinforcement  38 . The sleeve  29  can be pulled over the lock body reinforcement  38  once the lock cylinder  40  has been inserted into the lock body reinforcement  38  in the explained manner and the wall sections of the lock body reinforcement  38  have been bent into their final alignment. After the sleeve  29  has been pulled over, the sleeve  29  is fixed at the lock body reinforcement  38 , for example by peening over at four points along the periphery in the region of the latch projections  36 . 
         [0058]    With regard to the function of the joint lock  10 , the locking bar  18  is first introduced into the introduction opening  34  for a closing of the joint lock  10  on the introduction of the locking bar  18  into the lock body  12 . The region of the first end  24  of the locking bar  18  surrounded by the plastic jacket  20  is in this respect urged into the lock body  12 . If no key  32  is introduced into the lock cylinder  40 , the rotating latch  54  is located in the locking position. On the introduction of the locking bar  18 , the elevated securing portion  76  is led past the cut-out  70  until the elevated securing portion  76  comes into contact with the rotating latch  54  in the steep region  74 . If the locking bar  18  is introduced deeper into the lock body  12 , a force is transferred from the elevated securing portion  76  to the steep region of the rotating latch  54 , whereby a rotation of the rotating latch  54  against its preload about the axis of rotation of the lock cylinder  40  is triggered (clockwise in  FIG. 3   a ). The rotating latch  54  is temporarily rotated into the release position by the rotation of the rotating latch triggered in this manner. For this purpose, the cylinder core  50  of the lock cylinder  40  does not have to carry out any rotation since, as explained, sufficient rotational clearance is provided between the abutment edge  46  of the cylinder core  50  and the second abutment edge  64  of the rotating latch  54  and since the explained peripheral clearance  56  of the rotating latch  54  is also sufficiently large. 
         [0059]    The elevated securing portion  76  can be led so far past the rotating latch  54  by the rotation of the rotating latch  54  until the locking bar  18  and thus the elevated securing portion  76  has reached the position shown in the Figures. In the position shown, no force transmission takes place from the elevated securing position  76  to the steep region  74 , whereby the rotating latch  54  is automatically rotated back into the locking position by the force of the spring  66 . 
         [0060]    If an attempt is now made to pull the locking bar  18  out of the lock body  12 , the elevated securing portion  76  cants between the region of the outer jacket surface  69  of the rotating latch  54  and the lock body reinforcement  38 . Since the cut-out  70  of the rotating latch  54  is rotated away from the elevated securing portion  76  in the locking position, the elevated securing portion  76  cannot pass between the lock body reinforcement  38  and the rotating latch  54 . The locking bar  18  is thus latched in the lock body  12 . 
         [0061]    The elevated protection portion  78  acts in this locking position of the rotating latch  54  against a manipulation of the rotational position of the rotating latch  54  through the introduction opening  54  of the lock body  12 . The elevated protection portion  78  namely prevents that a flat tool is introduced along the locking bar  18  into the introduction opening  34  to urge the rotating latch  54  in the direction of its release position in the interior of the lock body  12 . 
         [0062]    If, in contrast, the authorized user wants to remove the locking bar  18  from the lock body  12 , for example to release his two-wheeler from a bicycle stand, he introduces the key  32  into the lock cylinder  40 . Subsequently, a rotational movement of the cylinder core  50  is carried out (clockwise in  FIG. 3   a ) using the key  32  by which the drive prolongation  42  is set into a rotational movement. The abutment edge  46  of the cylinder core  50  thereby drives the first abutment edge  62  of the coupling region  58  of the rotating latch  54  and likewise sets the rotating latch  54  in rotation (clockwise in  FIG. 3   a ). The cut-out  70  is brought into the movement path of the locking bar  18  (release position of the rotating latch  54 ) by the rotation of the rotating latch  54 , whereby the elevated securing portion  76  is released and can pass between the lock body reinforcement  38  and the rotating latch  54 . The locking bar  18  can thus be pulled out of the lock body  12 . 
         [0063]    Differing from the representation in the drawings, the locking bar  18  can be so short that the joint bar hoop  14  can be folded together into a common plane of extent of the joint bars  16  and of the locking bar  18  without the locking bar  18  being introduced into the lock body  12 . The joint lock  10  can hereby be stored or transported in the folded together state, with the locking bar  18  being able to be introduced into the introduction opening  34  of the lock body  12  for a subsequent locking of the joint lock  10  without the locking bar  18  first having to be released from the lock body  12  by means of the key  32 . Since—as explained—also no key actuation of the lock cylinder  40  is necessary to lock the locking bar  18  to the lock body  12 , the use of the joint lock  10  is thus particularly comfortable.